Exchangeable lens having a settable aperture and camera body that captures an image by an optical system which has a settable aperture

ABSTRACT

A lens barrel including: an optical system which includes a focus adjustment optical system; an aperture which limits the light beam which pass through the optical system to predetermined range at the time of detection of the focus state of the optical system; a drive which drives the focus adjustment optical system; a memory which stores a first predetermined value which is a aperture value within the predetermined range; and a transmitter which sends the first predetermined value to the camera body.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation of application Ser. No. 13/485,361 filed May 31,2012, which claims the benefit of U.S. Provisional Application No.61/587,378 filed Jan. 17, 2012; U.S. Provisional Application No.61/587,366 filed Jan. 17, 2012; U.S. Provisional Application No.61/587,328 filed Jan. 17, 2012; U.S. Provisional Application No.61/586,456 filed Jan. 13, 2012; U.S. Provisional Application No.61/586,433 filed Jan. 13, 2012; and U.S. Provisional Application No.61/586,430 filed Jan. 13, 2012, which claims the benefit of JapanesePatent Application No. 2011-191352 filed Sep. 2, 2011; Japanese PatentApplication No. 2011-195110 filed Sep. 7, 2011; Japanese PatentApplication No. 2011-191359 filed Sep. 2, 2011; Japanese PatentApplication No. 2011-151501 filed Jul. 8, 2011; Japanese PatentApplication No. 2011-146205 filed Jun. 30, 2011; and Japanese PatentApplication No. 2011-121337 filed May 31, 2011. The disclosure of theprior applications is hereby incorporated by reference herein in itsentirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a lens barrel and camera body.

2. Description of the Related Art

In the past, there has been known an imaging apparatus which uses theoutput of focus detection pixels which are provided at the imagingpickup device as the basis to detect the shift amount of an image planeof an optical system and thereby detect a focus state of the opticalsystem. As such an imaging apparatus, for example, one is known whichprevents the occurrence of vignetting at the time of focus detection byperforming focus detection while setting the aperture value of theoptical system at a value smaller (more opening side) than apredetermined aperture value (for example, see Japanese PatentPublication (A) No. 2010-217618).

SUMMARY OF THE INVENTION

However, in the prior art, when changing the aperture value of theoptical system from the aperture value at the time of focus detection tothe capture aperture value to capture an image, sometimes the change ofthe aperture value led to movement of the image plane of the opticalsystem and as a result it was not possible to capture an image focusedon the object.

The problem to be solved by the present invention is to provide a lensbarrel which can capture an image well.

The present invention solves the above problem by the following means.Note that, below, the explanation will be given while attachingreference numerals which correspond to parts in the drawings which showembodiments of the present invention, but the reference numerals areonly for facilitating understanding of the invention and do not limitthe invention.

A lens barrel according to a first aspect of the present inventioncomprising; an optical system which includes a focus adjustment opticalsystem (32); an aperture (34) which limits the light beam which passthrough the optical system to predetermined range at the time ofdetection of the focus state of the optical system; a drive (36) whichdrives the focus adjustment optical system; a memory (37) which stores afirst predetermined value which is a aperture value within thepredetermined range; and a transmitter (37) which sends the firstpredetermined value to the camera body.

In the lens barrel according to the present invention, the firstpredetermined value is a limit value of the opening side of the aperturevalue of the optical system at the time of detection of the focus stateof the optical system.

In the lens barrel according to the present invention, the drive (36)uses a focus state of the optical system as the basis to drive the focusadjustment optical system (32) in an optical axis direction.

In the lens barrel according to the present invention, the memory (39)stores the first predetermined value as a number of closing steps froman open aperture value of the optical system.

A lens barrel according to a second aspect of the present inventioncomprising; an optical system which includes a focus adjustment opticalsystem (32); an aperture (34) which limits the light beam; a drive (36)which drives the focus adjustment optical system; a memory (39) whichstores a variable amount, defined as an amount by which the aperturevalue of the optical system can be changed from the capture aperturevalue when capturing an image at the time of detection of the focusstate of the optical system, in accordance with the capture aperturevalue; and a transmitter (37) which sends the variable amount to thecamera body.

In the lens barrel according to the present invention, the aperture (34)limits a light beam which pass through the optical system, the drive(36) uses a focus state of the optical system as the basis to drive thefocus adjustment optical system in an optical axis direction.

In the lens barrel according to the present invention, the memory (39)stores as an opening side variable amount a variable amount of anopening side from the capture aperture value in the variable amounts andstores as a closing side variable amount a variable amount of a closingside from the capture aperture value in the variable amounts, and theopening side variable amount is smaller than the closing side variableamount.

In the lens barrel according to the present invention, the memory (39)stores the variable amount as a number of closing steps from the captureaperture value.

A lens adapter according to the present invention is a lens adapterwhich is interposed between a lens barrel (3) and a camera body (2) soas to connect the lens barrel and the camera body, comprising: a firstcommunicator (51) which communicates with the lens barrel; a secondcommunicator (51) which communicates with the camera body; a memory (52)which stores an opening side limit value, defined as a limit value of anopening side of the aperture value of the optical system, for each typeof lens barrel; an identifier (51) which makes the first communicatoracquire lens information from the lens barrel and which uses the lensinformation as the basis to identify the type of the lens barrel; and atransmitter (51) which sends an opening side limit value whichcorresponds to the identified lens barrel by the second communicator tothe camera body.

In the lens adapter according to the present invention, the memory (52)stores an opening side limit value, defined as the limit value of theopening side of the aperture value of the optical system at the time ofdetection of the focus state of the optical system, for each type oflens barrel (3).

In the lens adapter according to the present invention, the transmitter(51) sends a preset predetermined opening side limit value by the secondcommunicator (51) to the camera body (2) when the lens information whichwas acquired from the lens barrel (3) cannot be used as the basis toidentify the type of the lens barrel.

In the lens adapter according to the present invention, the memory (52)stores the opening side limit value as a number of closing steps from anopen aperture value of the optical system.

A camera body according to a first aspect of the present inventioncomprising: an imaging unit (22) which captures an image obtained by anoptical system and outputs an image signal which corresponds to thecaptured image; a focus detector (21) which uses the image signal as thebasis to detect a focus state of the optical system; a receiver (21)which receives from a lens barrel (3) a first predetermined value,defined as a limit value of the opening side of the aperture value ofthe optical system at the time of focus detection by the focus detector;a memory (29) which stores as a second predetermined value a limit valueof the closing side of the aperture value of the optical system at thetime of using the focus detector for focus detection; a controller (21)which sets the aperture value of the optical system in a range betweenthe first predetermined value and the second predetermined value at thetime of using the focus detector for focus detection; and a transmitter(21) which sends the aperture value which was set by the controller tothe lens barrel.

In the camera body according to the present invention, the firstpredetermined value is a limit value of the opening side of the aperturevalue of the optical system at the time of focus detection, the secondpredetermined value is a limit value of the closing side of the aperturevalue of the optical system at the time of focus detection.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection to the capture aperturevalue when capturing an image or a value at the opening side from thecapture aperture value.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection at a value at the closingside from the open aperture value of the optical system.

In the camera body according to the present invention, the imaging unit(22) has a plurality of capture-use pixels (221) which are arranged twodimensionally and a plurality of focus detection-use pixels (222 a,222b) which are arranged one dimensionally or two dimensionally while mixedwith the capture-use pixels; and the focus detector (21) can performfocus detection by at least one system of focus detection by the phasedifference detection system which uses the image signals which wereoutput from the focus detection-use pixels as the basis to detect ashift amount of an image plane obtained by the optical system andthereby detect a focus state of the optical system and focus detectionby the contrast detection system which uses the image signals which wereoutput from the capture-use pixels as the basis to calculate anevaluation value relating to the contrast of an image obtained by theoptical system and uses the calculated evaluation value as the basis todetect a focus state of the optical system.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection at the capture aperturevalue when the capture aperture value when capturing an image is a valueat the opening side from the opening side limit value.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection at the closing side limitvalue when the capture aperture value when capturing an image is a valueat the closing side from the second predetermined value.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection in a range of the firstpredetermined value and the second predetermined value when the captureaperture value when capturing an image is a value at the closing sidefrom the second predetermined value and sets the aperture value of theoptical system at the time of using the focus detector for focusdetection in a range of the first predetermined value and the secondpredetermined value when the capture aperture value is a value the sameas the second predetermined value or a value at the opening side fromthe second predetermined value.

In the camera body according to the present invention, the lens barrel(3) is designed to be able to be mounted through a lens adapter, and,when mounting the lens barrel through the lens adapter, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection at the second predeterminedvalue when the capture aperture value when capturing an image is a valueat the closing side from the second predetermined value and sets theaperture value of the optical system at the time of using the focusdetector for focus detection at the capture aperture value when thecapture aperture value is a value the same as the second predeterminedvalue or a value at the opening side from the second predeterminedvalue.

A camera body according to a second aspect of the present inventioncomprising: an imaging unit (22) which captures an image obtained by anoptical system and outputs an image signal which corresponds to thecaptured image; a focus detector (21) which uses the image signal as thebasis to detect a focus state of the optical system; an acquiring unit(21) which acquires a variable amount which corresponds to a currentcapture aperture value from the lens barrel (3) from variable amountswhich can change the aperture value of the optical system from thecapture aperture value when capturing an image at the time of detectionof the focus state of the optical system; a controller (21) which setsthe aperture value of the optical system in the range of the variableamount which corresponds to the capture aperture value at the time ofusing the focus detector for focus detection; and a transmitter (21)which sends the aperture value which is set by the controller to thelens barrel.

In the camera body according to the present invention, the imaging unit(22) has a plurality of capture-use pixels (221) which are arranged twodimensionally and a plurality of focus detection-use pixels (222 a,222b) which are arranged one dimensionally or two dimensionally while mixedwith the capture-use pixels, and the focus detector (21) can performfocus detection by at least one system of focus detection by the phasedifference detection system which uses the image signals which wereoutput from the focus detection-use pixels as the basis to detect ashift amount of an image plane obtained by the optical system andthereby detect a focus state of the optical system and focus detectionby the contrast detection system which uses the image signals which wereoutput from the capture-use pixels as the basis to calculate anevaluation value relating to the contrast of an image obtained by theoptical system and uses the calculated evaluation value as the basis todetect a focus state of the optical system.

A camera body according to a third aspect of the present invention is acamera body which enables a lens barrel (3) to be mounted by a lensadapter (5 a), wherein an imaging unit (22) which captures an imageobtained by an optical system, and which outputs an image signal whichcorresponds to the captured image; a focus detector (21) which uses theimage signal as the basis to detect a focus state of the optical system;a receiver (21) which receives from the lens adapter an opening sidelimit value, defined as a limit value of an opening side of an aperturevalue of the optical system at the time of using the focus detector forfocus detection; a memory (29) which stores as a closing side limitvalue a limit value of a closing side of the aperture value of theoptical system at the time of using the focus detector for focusdetection; a controller (21) which sets the aperture value of theoptical system in a range between the opening side limit value and theclosing side limit value at the time of using the focus detector forfocus detection; and a transmitter (21) which sends the aperture valuewhich is set by the controller through the lens adapter to the lensbarrel.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection at the capture aperturevalue when capturing an image or a value at the opening side from thecapture aperture value.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection at a value at the closingside from an open aperture value of the optical system.

In the camera body according to the present invention, the imaging unit(22) has a plurality of capture-use pixels (221) which are arranged twodimensionally and a plurality of focus detection-use pixels (222 a,222b) which are arranged one dimensionally or two dimensionally while mixedwith the capture-use pixels, and the focus detector (21) can performfocus detection by at least one system of focus detection by the phasedifference detection system which uses the image signals which wereoutput from the focus detection-use pixels as the basis to detect ashift amount of an image plane obtained by the optical system andthereby detect a focus state of the optical system and focus detectionby the contrast detection system which uses the image signals which wereoutput from the capture-use pixels as the basis to calculate anevaluation value relating to the contrast of an image obtained by theoptical system and uses the calculated evaluation value as the basis todetect a focus state of the optical system.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection at the capture aperturevalue when the capture aperture value when capturing an image is a valueat the opening side from the opening side limit value.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection at the closing side limitvalue when the capture aperture value when capturing an image is a valueat a closing side from the closing side limit value.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the time of usingthe focus detector (21) for focus detection in the range of the openingside limit value and the closing side limit value when the captureaperture value when capturing an image is a value at the closing sidefrom the closing side limit value and sets the aperture value of theoptical system at the time of using the focus detector for focusdetection in a range of the opening side limit value and the captureaperture value when the capture aperture value is a value the same asthe closing side limit value or a value at the opening side from theclosing side limit value.

A camera body according to a fourth aspect of the present inventioncomprising: an imaging unit (22) which outputs an image signal whichcorresponds to a captured image; a focus detector (21) which detects afocus state of an optical system; a focus adjusting controller (21)which controls the drive of the focus adjustment optical system (32);and a controller (21) which makes the focus detector perform focusdetection in the state making the aperture value the open aperturevalue, which closes the aperture while driving the focus adjustmentoptical system based on the results of the focus detection, and whichmakes the focus detector perform focus detection in the state where theaperture is closed.

In the camera body according to the present invention, the imaging unit(22) captures an image obtained by the optical system and outputs animage signal which corresponds to the captured image, the focus detector(21) uses the image signal as the basis to detect a focus state of theoptical system, the focus adjusting controller (21) uses the result offocus detection by the focus detector as the basis to drive the focusadjustment optical system in the optical axis direction so as to adjustthe focus of the optical system, and the controller (21) makes the focusdetector detect the focus in the state where the aperture value of theoptical system is made the open aperture value, uses the results of thefocus detection as the basis to make the focus adjusting controllerstart the drive of the focus adjustment optical system, closes theaperture during the drive operation of the focus adjustment opticalsystem, and makes the focus detector detect the focus in the state wherethe aperture is closed.

In the camera body according to the present invention, furthercomprising a judgment unit (21) which detects a brightness of the objectand uses the detected brightness of the object as the basis to judge ifillumination by a light which emits illumination light at an object isnecessary, wherein when it is judged that illumination by the light isnecessary, the controller (21) makes the focus detector (21) detect thefocus in the state where the aperture value of the optical system ismade the open aperture value, uses the results of the focus detection asthe basis to make the focus adjusting controller (21) stall the drive ofthe focus adjustment optical system, closes the aperture (34) during thedrive operation of the focus adjustment optical system, and makes thefocus detector detect the focus in the state where the aperture isclosed.

In the camera body according to the present invention, furthercomprising an acquiring unit (21) which acquires the limit value of theopening side of the aperture value of the optical system at the time ofusing the focus detector (21) for focus detection as the opening sidelimit value from the lens barrel (3), wherein the controller (21) closesthe aperture (34) so that the aperture value of the optical systembecomes the same value as the opening side limit value or a value at theclosing side from the opening side limit value during the driveoperation of the focus adjustment optical system when the opening sidelimit value could be obtained from the lens barrel.

In the camera body according to the present invention, furthercomprising an acquiring unit (21) which acquires the limit value of theopening side of the aperture value of the optical system at the time ofusing the focus detector (21) for focus detection as the opening sidelimit value from the lens barrel (3), wherein the controller (21) makesthe focus detector (21) detect the focus in the state where the aperturevalue of the optical system is made the opening side limit value, usesthe results of the focus detection as the basis to make the focusadjusting controller (21) start the drive operation of the focusadjustment optical system, closes the aperture (34) during the driveoperation of the focus adjustment optical system (32), and makes thefocus detector detect the focus in the state where the aperture isclosed when the opening side limit value could be obtained from the lensbarrel.

In the camera body according to the present invention, the controller(21) makes the focus detector (21) detect the focus while using theaperture value of the optical system as the open aperture value when thefocus state of the optical system cannot be detected in the state wherethe aperture value of the optical system is made the opening side limitvalue, uses the results of the focus detection as the basis to make thefocus adjusting controller (21) start the drive operation of the focusadjustment optical system, closes the aperture (34) during the driveoperation of the focus adjustment optical system, and makes the focusdetector detect the focus in the state where the aperture is closed.

In the camera body according to the present invention, the controller(21) closes the aperture (34) so that the aperture value of the opticalsystem becomes the capture aperture value when capturing an image duringthe drive operation of the focus adjustment optical system (32).

In the camera body according to the present invention, furthercomprising a memory (29) which stores the limit value of the closingside of the aperture value of the optical system at the time of usingthe focus detector for focus detection as the closing side limit value,wherein the controller (21) closes the aperture (34) so that theaperture value of the optical system becomes the closing side limitvalue during the drive operation of the focus adjustment optical system(32) when the capture aperture value when capturing an image is a valueat the closing side from the closing side limit value.

In the camera body according to the present invention, the imaging unit(22) has a plurality of capture-use pixels (221) which are arranged twodimensionally and a plurality of focus detection-use pixels (222 a,222b) which are arranged one dimensionally or two dimensionally while mixedwith the capture-use pixels, and the focus detector (21) can performfocus detection by at least one system of focus detection by the phasedifference detection system which uses the image signals which wereoutput from the focus detection-use pixels as the basis to detect ashift amount of an image plane obtained by the optical system andthereby detect a focus state of the optical system and focus detectionby the contrast detection system which uses the image signals which wereoutput from the capture-use pixels as the basis to calculate anevaluation value relating to the contrast of an image obtained by theoptical system and uses the calculated evaluation value as the basis todetect a focus state of the optical system.

A camera body according to a fifth aspect of the present inventioncomprising: an imaging unit (22) which outputs an image signal whichcorresponds to a captured image; a focus detector (21) which detects afocus state of an optical system; and a controller (21) which controlsan aperture (34) so that the aperture value of the optical system islimited to a value of the predetermined aperture value or less at thetime of focus detection by the focus detector when a capture aperturevalue at the time of capturing an image obtained by the optical systemis larger than a predetermined aperture value.

In the camera body according to the present invention, the imaging unit(22) captures an image formed by the optical system and outputs an imagesignal which corresponds to the captured image, and the focus detector(21) uses the output of a focus detection pixel (222 a, 222 b) which isprovided at the light receiving surface of the imaging unit as the basisto detect a shift amount of an image plane which is obtained by theoptical system so as to detect a focus state of the optical system.

In the camera body according to the present invention, furthercomprising an exposure controller (21) which uses exposure controlvalues which include an exposure time, capture sensitivity, and aperturevalue as the basis for exposure control for the imaging unit (22),wherein the exposure controller performs exposure control while changingat least one of the exposure time and the capture sensitivity whenexposure suitable for focus detection can be obtained by changing atleast one of the exposure time and the capture sensitivity while leavingthe aperture value of the optical system fixed at the time of using thefocus detector (21) for focus detection and makes the controller (21)change the aperture value of the optical system when exposure suitablefor focus detection cannot be obtained while leaving the aperture valueof the optical system fixed.

In the camera body according to the present invention, the controller(21) changes the aperture value of the optical system in the range ofthe predetermined aperture value or less when exposure suitable forfocus detection cannot be obtained while leaving the aperture value ofthe optical system fixed.

In the camera body according to the present invention, the camera bodyis further provided with a focus adjuster which drives a focusadjustment optical system (32) in the optical axis direction so as toadjust the focus of the optical system and a starter (28) which startsup focus adjustment by the focus adjuster, and the exposure controller(21) uses the starter to perform exposure control before the focusadjustment is started up.

In the camera body according to the present invention, furthercomprising a display (26) which displays a through-the-lens image whichcorresponds to an image which is repeatedly captured by the imaging unit(22).

In the camera body according to the present invention, furthercomprising a mode setter (28) which can set a moving image capture mode,wherein the controller (21) sets the aperture value of the opticalsystem at the capture aperture value when the moving image capture modeis set.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the captureaperture value at the time of capturing an image obtained by the opticalsystem.

A camera body according to a sixth aspect of the present inventioncomprising: an imaging unit (22) which outputs an image signal whichcorresponds to a captured image; a focus detector (21) which detects afocus state of an optical system; and a controller (21) which sets anaperture value of an aperture at a second for focus detection or a valueat the opening side from the second predetermined value before a shutterrelease button is half pressed.

In the camera body according to the present invention, furthercomprising a display (26) which displays a through-the-lens image whichcorresponds to an image which is repeatedly captured by the imaging unit(22), wherein the imaging unit captures an image obtained by the opticalsystem and outputs an image signal which corresponds to the capturedimage, the focus detector (21) uses outputs of the focus detectionpixels (221) which are provided at the light receiving surface of theimaging unit as the basis to detect a shift amount of an image planeobtained by the optical system so as to detect a focus state of theoptical system, and the controller (21) sets the aperture value of theoptical system at the second predetermined value or a value at theopening side from the second predetermined value in the period after thestart of display of the through-the-lens image by the display and beforea half press operation of a shutter release button.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at a capture aperturevalue when capturing a moving image by recording an image which isrepeatedly captured by the imaging unit (22).

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system so that the aperturevalue of the optical system becomes a value in the range of the secondpredetermined value and a first predetermined value which is at theopening side from the second predetermined value for focus detection inthe period after the start of display of the through-the-lens image bythe display (26) and before a half press operation of a shutter releasebutton.

In the camera body according to the present invention, furthercomprising a judging unit (21) which detects a brightness of the objectand uses the detected brightness of the object as the basis to judge iflighting by a light which emit illumination light to an object isnecessary at the time of using the focus detector (21) for focusdetection, wherein the controller (21) sets the aperture value of theoptical system at a first predetermined value for focus detection or avalue at the opening side from the first predetermined value in theperiod after the display of the through-the-lens image is started by thedisplay (26) and before a half press operation of a shutter releasebutton when it is judged that illumination by the light is necessary.

In the camera body according to the present invention, the controller(21) changes the aperture value of the optical system from a valuebefore a shutter release button is half pressed when a reliability ofthe shift amount which was detected by the focus detector (21) is apredetermined value or less after a half press operation of the shutterrelease button is performed.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the captureaperture value in the period after the start of the display of thethrough-the-lens image by the display (26) and before a shutter releasebutton is half pressed when a capture aperture value at the time ofcapturing an image is a value at the opening side from a firstpredetermined value for focus detection.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system at the secondpredetermined value in the period after the start of the display of thethrough-the-lens image by the display (26) and before a shutter releasebutton is half pressed when a capture aperture value at the time ofcapturing an image is a value at the closing side from the secondpredetermined value.

In the camera body according to the present invention, the controller(21) sets the aperture value of the optical system so that the aperturevalue of the optical system becomes a value within the range of thesecond predetermined value and a first predetermined value which is atthe opening side from the second predetermined value for focus detectionin the period after the display of the through-the-lens image is startedby the display (26) and before a shutter release button is half pressedwhen the capture aperture value when capturing an image is a value at aclosing side from the second predetermined value and sets the aperturevalue of the optical system so that the aperture value of the opticalsystem becomes a value within the range between the capture aperturevalue and the first predetermined value for focus detection in theperiod after the display of the through-the-lens image is started by thedisplay and before a shutter release button is half pressed when thecapture aperture value when capturing an image is a value the same asthe second predetermined value or a value at the opening side from thesecond predetermined value.

A lens barrel according to a third aspect of the present inventioncomprising: an optical system which includes a focus adjustment opticalsystem (32); an aperture (34) which limits the light beam which passthrough the optical system to predetermined range at the time ofdetection of the focus state of the optical system; a drive (36) whichdrives the focus adjustment optical system; a memory (37) which stores aminimum aperture value of the predetermined range; and a transmitter(37) which sends the minimum aperture value to the camera body.

According to the present invention, it is possible to capture an imagewell.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram which shows a camera according to a firstembodiment.

FIG. 2 is a front view which shows a focus detection position in animage pickup device which is shown in FIG. 1.

FIG. 3 is a front view which enlarges the part III of FIG. 2 andschematically shows an array of focus detection pixels 222 a, 222 b.

FIG. 4 is a front view which shows one of the capture pixels 221enlarged.

FIG. 5A is a front view which shows one of the focus detection pixels222 a enlarged, while FIG. 5B is a front view which shows one of thefocus detection pixels 222 b enlarged.

FIG. 6 is a cross-sectional view which shows one of the capture pixels221 enlarged.

FIG. 7A is a cross-sectional view which shows one of the focus detectionpixels 222 a enlarged, while FIG. 7B is a cross-sectional view whichshows one of the focus detection pixels 222 b enlarged.

FIG. 8 is a cross-sectional view along the line VIII-VIII of FIG. 3.

FIG. 9 is a flow chart which shows the operation of a camera accordingto a first embodiment.

FIG. 10 is a view which shows an example of the relationship between anaperture value at the time of focus detection which was set at the firstembodiment and a capture aperture value.

FIG. 11 is a flow chart which shows scan operation processing of stepS118.

FIG. 12 is a block diagram which shows a camera according to a secondembodiment.

FIG. 13 is a view which shows an example of the relationship between anaperture value at the time of focus detection which was set at thesecond embodiment and a capture aperture value.

FIG. 14 is a view for explaining a variable amount of the aperture valuein a third embodiment.

FIG. 15 is a flow chart which shows the operation of a camera accordingto the third embodiment.

FIG. 16 is a view for explaining another example of the variable amountof the aperture value.

FIG. 17 is a block diagram which shows a camera according to a fourthembodiment.

FIG. 18 is a flow chart which shows the operation of a camera accordingto the fourth embodiment.

FIG. 19 is a flow chart which shows the operation of a camera accordingto a fifth embodiment.

FIG. 20 is a view which shows an example of the relationship between anaperture value at the time of focus detection which was set at the fifthembodiment and a capture aperture value.

FIG. 21 is a flow chart which shows the operation of a camera accordingto a sixth embodiment.

FIG. 22 is a flow chart (part 1) which shows the operation of a cameraaccording to a seventh embodiment.

FIG. 23 is a flow chart (part 2) which shows the operation of a cameraaccording to a seventh embodiment.

DESCRIPTION OF EMBODIMENTS

Below, embodiments of the present invention will be explained based onthe drawings.

First Embodiment

FIG. 1 is a view of the configuration of principal parts which shows adigital camera 1 according to an embodiment of the present invention.The digital camera 1 of the present embodiment (below, simply referredto as the “camera 1”) is comprised of a camera body 2 and a lens barrel3. These camera body 2 and lens barrel 3 are detachably connected by amount 4.

The lens barrel 3 is an exchangeable lens which can be detachablyattached to the camera body 2. As shown in FIG. 1, the lens barrel 3houses a capture optical system which includes lenses 31, 32, and 33 andan aperture 34.

The lens 32 is a focus lens which can move along the optical axis L1direction so as to adjust the focal distance of a capture opticalsystem. The focus lens 32 is provided to be able to move along theoptical axis L1 of the lens barrel 3 and is detected in position by anencoder 35 while being adjusted in position by a focus lens drive motor36.

The specific configuration of the movement mechanism along the opticalaxis L1 of this focus lens 32 is not particularly limited. If giving oneexample, a rotating barrel is inserted in a rotatable manner inside afixed barrel which is fixed to the lens barrel 3, a helicoid groove isformed at an inner circumference of this rotating barrel, and an end patL of a lens frame which fixes the focus lens 32 is engaged with thehelicoid groove. Further, the focus lens drive motor 36 is used to makethe rotating barrel rotate by making the focus lens 32 which is fixed tothe lens frame move linearly along the optical axis L1.

As explained above, the rotating barrel is made to rotate with respectto the lens barrel 3 so as to make the focus lens 32 which is fixed tothe lens frame move linearly in the optical axis L1 direction, but thedrive source, constituted by the focus lens drive motor 36, is providedat the lens barrel 3. The focus lens drive motor 36 and the rotatingbarrel are coupled by, for example, a transmission which is comprised ofa plurality of gears. If driving a drive shaft of the focus lens drivemotor 36 to rotate in either direction, the drive force is transmittedto the rotating barrel by a predetermined gear ratio and, further, therotating barrel rotates in either of the directions whereby the focuslens 32 which is fixed to the lens frame moves linearly in eitherdirection of the optical axis L1. Note that, if the drive shaft of thefocus lens drive motor 36 is driven to rotate in the opposite direction,the plurality of gears which faun the transmission also rotate in theopposite direction and the focus lens 32 moves linearly in the oppositedirection of the optical axis L1.

The position of the focus lens 32 is detected by an encoder 35. Asalready explained, the position of the focus lens 32 in the optical axisL1 direction is correlated with the rotational angle of the rotatingbarrel, so for example can be found if detecting the relative rotationalangle of the rotating barrel with respect to the lens barrel 3.

As the encoder 35 of the present embodiment, one which detects rotationof a rotating disk which is coupled with rotational drive of therotating barrel is detected by a photo interpreter or other photo sensorand outputs a pulse signal corresponding to the rotational speed, onewhich makes a brush contact which is provided at one of a fixed barreland rotating barrel contact an encoder pattern on the surface of aflexible printed circuit board which is provided at the other anddetects a change in a contact position corresponding to an amount ofmovement of the rotating barrel (either in the rotational direction oroptical axis direction) by a detection circuit etc. can be used.

The focus lens 32 can move in the optical axis L1 direction in theinterval from the end at the camera body side (also called the “nearend”) to the end at the object side (also called the “infinite end”) dueto rotation of the above-mentioned rotating barrel. Incidentally, thecurrent position information of the focus lens 32 which was detected byan encoder 35 is sent through a lens controller 37 to a later explainedcamera controller 21. The focus lens drive motor 36 is driven by thedrive position of the focus lens 32 which is computed based on theinformation being sent from the camera controller 21 through the lenscontroller 37.

The aperture 34 is configured to limit the amount of light beam whichpass through the capture optical system to reach the image pickup device22 and to adjust the aperture size centered at the optical axis L1 foradjusting the amount of defocus. The aperture size by the aperture 34 isadjusted by sending the aperture size corresponding to the aperturevalue which was computed in, for example, the automatic exposure modefrom the camera controller 21 through the lens controller 37. Further,by manual operation by the operating unit 28 which is provided at thecamera body 2, the aperture size corresponding to the set captureaperture value is input from the camera controller 21 to the lenscontroller 37. The aperture size of the aperture 34 is detected by a notshown aperture sensor, while the current aperture size is found by thelens controller 37.

Further, in the present embodiment, the lens controller 37 stores thelimit value of the opening side of the aperture value of the opticalsystem at the time of detection of the focus state of the optical systemas the opening side limit value in advance in a memory 39. Here, forexample, when making the aperture value at the time of detection of thefocus state of the optical system F1.4 and making the capture aperturevalue at the time of capturing the image F2.8, since the captureoperation is performed after focus detection, when changing the aperturevalue of the optical system from the aperture value F1.4 at the time offocus detection to the capture aperture value F2.8, sometimes themovement of the image plane accompanying a change of the aperture valuecauses the focal position which was detected at the time of focusdetection to end up deviating from the depth of field of the opticalsystem at the time of capturing an image and makes it impossible tocapture an image focused at the object which had been focused at thetime of focus detection. In particular, this trend becomes greater themore to the opening side the aperture value of the optical system.Therefore, in such a case, for example, by limiting the aperture valueat the time of detection of the focus state of the optical system not atF1.4, but up to F2, it is possible to suppress the amount of movement ofthe image plane accompanying change of the aperture value and to capturean image focused on the object even if changing the aperture value ofthe optical system from the aperture value at the time of detection ofthe focus state to the capture aperture value. The opening side limitvalue, in this way, is the limit value of the opening side of theaperture value of the optical system which enables an image to becaptured well even if changing the aperture value of the optical systemfrom the aperture value at the time of focus detection to the captureaperture value and is stored in advance at the lens controller 37 as aunique value for each lens barrel 3.

Further, in the present embodiment, the lens controller 37 stores theopening side limit value as the number of closing steps from the openaperture value in the memory 39. For example, when the opening sidelimit value is an aperture value (F-value) of F2, the open aperturevalue is F1.2, and the number of closing steps of the aperture 34 forchanging the aperture value of the optical system from the open aperturevalue F1.2 to the opening side limit value F2 is two steps, the cameracontroller 37 stores the opening side limit value as two steps. Bystoring the opening side limit value as the number of closing steps fromthe open aperture value in this way, for example, even when the lensposition of the zoom lens is changed, the open aperture valuecorresponding to the lens position of the zoom lens may be used as thebasis to find the opening side limit value corresponding to the lensposition of the zoom lens. There is no need to store the open aperturevalue for each lens position of the zoom lens. Note that, theabove-mentioned open aperture value, opening side limit value, andnumber of closing steps are examples. The invention is not limited tothese values.

On the other hand, the camera body 2 is provided with an image pickupdevice 22 which receives a light beam L1 from the capture optical systemat a predetermined focal plane of the capture optical system and isprovided with a shutter 23 at a front surface of the same. The imagepickup device 22 is comprised of a CCD, CMOS, or other device. Itconverts a received optical signal to an electric signal which it sendsto the camera controller 21. The capture image information which is sentto the camera controller 21 is successively sent to a liquid crystaldrive circuit 25 and displayed at an electronic viewfinder (EVF) 26 ofthe viewing optical system. When the release button (not shown) which isprovided at the operating unit 28 is fully pressed, the capture imageinformation is recorded at a recording medium, that is, a memory 24. Thememory 24 used may be either of a detachable card type memory orbuilt-in type memory. At the front of the surface of the image pickupdevice 22, an infrared ray cut filter for cutting infrared light and anoptical low pass filter for preventing aliasing noise of the image arearranged. The details of the structure of the image pickup device 22will be explained later.

The camera body 2 is provided with a camera controller 21. The cameracontroller 21 is electrically connected with the lens controller 37 byan electrical signal contact 41 which is provided at the mount 4,receives the lens information from this lens controller 37, and sendsthe amount of defocus, the aperture size, and other information to thelens controller 37. Further, the camera controller 21, as explainedabove, reads the pixel output from the image pickup device 22, processesthe read pixel output in accordance with need by predeterminedinformation processing so as to generate image information, and outputsthe generated image information to the liquid crystal drive circuit 25of the electronic viewfinder 26 or the memory 24. Further, the cameracontroller 21 corrects the image information from the image pickupdevice 22, detects the focus adjusting state of the lens barrel 3, theaperture adjusting state, etc., and otherwise oversees the control ofthe camera 1 as a whole.

Further, the camera controller 21 also uses the pixel data which wasread out from the image pickup device 22 as the basis to detect thefocus state of the capture optical system by the phase detection systemand to detect the focus state of the optical system by the contrastdetection system. Note that, the method of detection of the focus statewill be explained later.

In addition, the camera controller 21 stores in advance the limit valueof the closing side of the aperture value of the optical system at thetime of focus detection in the memory 29 as the closing side limitvalue. This closing side limit value can be made the value the most atthe closing side among the aperture values which enable effectiveprevention of, for example, vignetting at the time of focus detectionand enable good focus detection precision to be obtained. Further, thecamera controller 21 uses the opening side limit value which wasreceived from the lens controller 37 and the closing side limit valuewhich was stored in the memory 29 as the basis for exposure control atthe time of focus detection. Note that, details of the exposure controlat the time of focus detection will be explained later.

The operating unit 28 includes a shutter release button, moving imagecapture button, and input switch for a photographer to set variousoperating modes of the camera 1 and is designed to enable switchingbetween an autofocus mode/manual focus mode. Further, the operating unit28 is also designed to be able to switch between a still image capturemode/moving image capture mode. The various modes which are set by thisoperating unit 28 are sent to the camera controller 21. The cameracontroller 21 is used to control the operation of the camera 1 as awhole. Further, the shutter release button includes a first switch SW1which becomes on by half pressing of the button and a second switch SW2which becomes on by full pressing of the button.

Further, the camera body 2 of the present embodiment is provided with alight 210 which emits illumination light for focus detection. Theemission of illumination light by the light 210 is controlled by acontrol signal from the camera controller 21 based on the output of theimage pickup device 22.

Next, the image pickup device 22 according to the present embodimentwill be explained.

FIG. 2 is a front view which shows an imaging plane of the image pickupdevice 22, while FIG. 3 is a front view which enlarges the part III ofFIG. 2 and schematically shows the arrangement of the focus detectionpixels 222 a and 222 b.

The image pickup device 22 of the present embodiment, as shown in FIG.3, is comprised of a plurality of capture pixels 221 arranged twodimensionally on the plane of the imaging plane, that is, is comprisedof green pixels G which have color filters which pass the wavelengthregion of the green color, red pixels R which have color filters whichpass the wavelength region of the red color, and blue pixels B whichhave color filters which pass the wavelength region of the blue color ina so-called “Bayer arrangement”. That is, two green pixels are arrangedon one diagonal line in four adjoining pixel groups 223 (dense squarelattice array), while one red pixel and blue pixel each are arranged onthe other diagonal line. This Bayer arrangement group of pixels 223 isused as a unit and the group of pixels 223 is repeatedly arranged twodimensionally on the imaging plane of the image pickup device 22 wherebyan image pickup device 22 is configured.

Note that, the arrangement of the unit pixel groups 223 can for examplebe made a dense hexagonal lattice arrangement in place of theillustrated dense square lattice. Further, the configuration andarrangement of the color filters are not limited to these. It is alsopossible to employ an arrangement of color correction filters (green: G,yellow: Ye, magenta: Mg, cyan: Cy).

FIG. 4 is a front view which shows one of the capture pixels 221enlarged, while FIG. 6 is a cross-sectional view. One capture pixel 221is comprised of a microlens 2211, a photoelectric converter 2212, and anot shown color filter. As shown by the cross-sectional view of FIG. 6,the photoelectric converter 2212 is built into the surface of thesemiconductor circuit board 2213 of the image pickup device 22 while themicrolens 2211 is formed at the surface of the same. The photoelectricconverter 2212 is shaped to receive by the microlens 2211 a capturedbundle of light which passes through the exit pupil of the captureoptical system (for example, F1.0) and receives the captured bundle oflight.

Further, at three locations of the center of the imaging plane of theimage pickup device 22 and symmetric positions at the right and leftfrom the center, instead of the above-mentioned capture pixels 221,focus detection pixel strings 22 a, 22 b, and 22 c which are comprisedof focus detection pixels 222 a and 222 b arrayed are provided. Further,as shown in FIG. 3, one focus detection pixel string is comprised of aplurality of focus detection pixels 222 a and 222 b arranged alternatelywhile adjoining each other in a row (22 a, 22 c, and 22 c). In thepresent embodiment, the focus detection pixels 222 a and 222 b aredensely arranged without provision of gaps at the positions of the greenpixels G and blue pixels B of the Bayer arrangement of the capturepixels 221.

Note that, the positions of the focus detection pixel strings 22 a to 22c which are shown in FIG. 2 are not limited to just the illustratedpositions. The strings may be arranged at any single position or twopositions and, further, may be arranged at positions of four or morelocations. Further, at the time of actual focus detection, aphotographer can manually operate the operating unit 28 so as to selectthe desired focus detection pixel string as the focus detection positionfrom the plurality of arranged focus detection pixel strings 22 a to 22c.

FIG. 5A is a front view which shows one of the focus detection pixels222 a enlarged, while FIG. 7A is a cross-sectional view of a focusdetection pixel 222 a. Further, FIG. 5B is a front view which shows oneof the focus detection pixels 222 b enlarged, while FIG. 7B is across-sectional view of the focus detection pixel 222 b. The focusdetection pixel 222 a, as shown in FIG. 5A, is comprised of a microlens2221 a and a semicircular shape photoelectric converter 2222 a. As shownin the cross-sectional view of FIG. 7A, photoelectric converters 2222 aare built into the surface of the semiconductor circuit board 2213 ofthe image pickup device 22 and microlenses 2221 a are formed at theirsurfaces. Further, each focus detection pixel 222 b, as shown in FIG.5B, is comprised of a microlens 2221 b and a photoelectric converter2222 b. As shown by the cross-sectional view of FIG. 7B, thephotoelectric converter 2222 b is built into the surface of thesemiconductor circuit board 2213 of the image pickup device 22 and themicrolens 2221 b is formed at its surface. Further, these focusdetection pixels 222 a and 222 b, as shown in FIG. 3, are arrangedalternately while adjoining each other in a row, whereby the focusdetection pixel strings 22 a to 22 c which are shown in FIG. 2 areformed.

Note that, the photoelectric converters 2222 a and 2222 b of the focusdetection pixels 222 a and 222 b are shaped so as to receive the lightbeam which pass through a predetermined region of the exit pupil of thecapture optical system (for example, F2.8) by the microlenses 2221 a and2221 b. Further, the focus detection pixels 222 a and 222 b are notprovided with color filters. The spectral characteristics are acombination of the spectral characteristics of the photodiode performingthe photoelectric conversion and the spectral characteristics of the notshown infrared cut filter. However, it is also possible to provide oneof the color filters the same as the capture pixels 221, for example, agreen filter.

Further, the photoelectric converters 2222 a and 2222 b of the focusdetection pixels 222 a and 222 b which are shown in FIG. 5A and FIG. 5Bwere made semicircular shapes, but the shapes of the photoelectricconverters 2222 a and 2222 b are not limited to this. They may be madeother shapes, for example, elliptical shapes, rectangular shapes, orpolygonal shapes.

Here, the so-called phase difference detection system which uses thepixel outputs of the above-mentioned focus detection pixels 222 a and222 b as the basis to detect the focus state of the capture opticalsystem will be explained.

FIG. 8 is a cross-sectional view along the line VIII-VIII of FIG. 3 andshows that the focus detection pixels 222 a-1, 222 b-1, 222 a-2, and 222b-2 which are arranged near the capture optical axis L1 and adjoin eachother receive the light beam AB1-1, AB2-1, AB1-2, and AB2-2 which areemitted from the distance measuring pupils 351 and 352 of the exit pupil350. Note that, in FIG. 8, among the plurality of focus detection pixels222 a and 222 b, only the ones which are positioned near the captureoptical axis L1 are illustrated, but the other focus detection pixelsother than the focus detection pixels which are shown in FIG. 8 are alsosimilarly configured to receive the light beam which are emitted fromthe pair of distance measuring pupils 351 and 352.

Here, the “exit pupil 350” is an image which is set at a position adistance D in front of the microlenses 2221 a and 2221 b of the focusdetection pixels 222 a and 222 b which are arranged at the predeterminedfocal plane of the capture optical system. The distance D is a valuewhich is unambiguously determined in accordance with the curvature andrefractive index of the microlens, the distance between the microlensand the photoelectric converter, etc. This distance D is called thedistance measuring pupil distance. Further, the “distance measuringpupils 351 and 352” mean images of the photoelectric converters 2222 aand 2222 b which are projected by the microlenses 2221 a and 2221 b ofthe focus detection pixels 222 a and 222 b.

Note that, in FIG. 8, the direction of arrangement of the focusdetection pixels 222 a-1, 222 b-1, 222 a-2, and 222 b-2 matches thedirection of alignment of the pair of distance measuring pupils 351 and352.

Further, as shown in FIG. 8, the microlenses 2221 a-1,2221 b-1, 2221a-2, and 2221 b-2 of the focus detection pixels 222 a-1, 222 b-1, 222a-2, and 222 b-2 are arranged near a predetermined focal plane of thecapture optical system. Further, the shapes of the photoelectricconverters 2222 a-1, 2222 b-1, 2222 a-2, and 2222 b-2 which are arrangedbehind the microlenses 2221 a-1, 2221 b-1, 2221 a-2, and 2221 b-2 areprojected at the exit pupils 350 separated by exactly the measureddistance D from the microlenses 2221 a-1, 2221 b-1, 2221 a-2, and 2221b-2. The projected shapes faun the distance measuring pupils 351 and352.

That is, the relative positional relationships of the microlenses andphotoelectric converters at the focus detection pixels are determined sothe projected shapes of the photoelectric converters of the focusdetection pixels (distance measuring pupils 351 and 352) match on theexit pupil 350 at the measuring distance D. Due to this, the projectiondirections of the photoelectric converters at the focus detection pixelsare determined.

As shown in FIG. 8, the photoelectric converter 2222 a-1 of the focusdetection pixel 222 a-1 outputs a signal corresponding to the strengthof the image which is formed on the microlens 2221 a-1 by the light beamAB1-1 which pass through the distance measuring pupil 351 and headtoward the microlens 2221 a-1. Similarly, the photoelectric converter2222 a-2 of the focus detection pixel 222 a-2 outputs a signalcorresponding to the strength of the image which is formed on themicrolens 2221 a-2 by the light beam AB1-2 which pass through thedistance measuring pupil 351 and head toward the microlens 2221 a-2.

Further, the photoelectric converter 2222 b-1 of the focus detectionpixel 222 b-1 outputs a signal corresponding to the strength of theimage which is formed on the microlens 2221 b-1 by the light beam AB2-1which pass through the distance measuring pupil 352 and head toward themicrolens 2221 b-1. Similarly, the photoelectric converter 2222 b-2 ofthe focus detection pixel 222 b-2 outputs a signal corresponding to thestrength of the image which is formed on the microlens 2221 b-2 by thelight beam AB2-2 which pass through the distance measuring pupil 352 andhead toward the microlens 2221 b-2.

Further, by arranging pluralities of the above-mentioned two types offocus detection pixels 222 a and 222 b in a line as shown in FIG. 3 andgrouping the outputs of the photoelectric converters 2222 a and 2222 bof the focus detection pixels 222 a and 222 b in output groups whichcorrespond to the distance measuring pupil 351 and the distancemeasuring pupil 352, data is obtained relating to the strengthdistribution of the pair of images which the bundles of focus detectionrays which pass through the distance measuring pupils 351 and thedistance measuring pupils 352 faun on the focus detection pixel string.Further, by processing this strength distribution data by correlationprocessing, phase difference detection processing, or other imagedeviation detection processing, it is possible to detect the amount ofimage deviation due to the so-called phase difference detection system.

Further, by processing the obtained amount of image deviation byconversion corresponding to the distance between centers of gravity ofthe pair of distance measuring pupils, it is possible to find thedeviation of the current focal plane (meaning the focal plane at thefocus detection position corresponding to the position of the microlensarray on a predetermined focal plane) from the predetermined focalplane, that is, the amount of defocus.

Note that, the processing of the amount of image deviation by the phasedifference detection system and the processing of the amount of defocusbased on this are performed by the camera controller 21.

Further, the camera controller 21 reads out the outputs of the capturepixels 221 of the image pickup device 22 and uses the read out pixeloutputs as the basis for processing the focal evaluation value. Thisfocal evaluation value can be found, for example, by extracting the highfrequency components of the image outputs from the capture pixels 221 ofthe image pickup device 22 using a high frequency pass filter andintegrating the same. Further, it can also be found by using two highfrequency pass filters with different cutoff frequencies to extract thehigh frequency components and integrating them.

Further, the camera controller 21 sends the lens controller 37 a controlsignal to drive the focus lens 32 by a predetermined sampling interval(distance), finds focal evaluation values at the different positions,and finds the position of the focus lens 32 where the focal evaluationvalue becomes maximum as the focal position, that is, performs focusdetection by the contrast detection system. Note that, when driving thefocus lens 32 while calculating the focal evaluation value and the focalevaluation value rises twice, then further drops twice, this focalposition can, for example, be found by interpolation or other processingusing these focal evaluation values.

Next, an example of operation of the camera 1 according to the firstembodiment will be explained. FIG. 9 is a flow chart which shows anexample of operation of the camera 1 according to the presentembodiment. Note that, the following operation is started by the powerof the camera 1 being turned on.

First, at step S101, the camera controller 21 is used to judge if amoving image is being captured. In the present embodiment, the cameracontroller 21 can judge that a moving image is being captured when, forexample, the photographer presses a moving image capture button which isprovided at the operating unit 28 and the moving image starts to becaptured or when, in the moving image capture mode, the photographerpresses a button for stating capture of the moving image (for example,shutter release button) and the moving image starts to be captured. Whenit is judged that a moving image is being captured, the routine proceedsto step S121, while when it is judged that a moving image is not beingcaptured, the routine proceeds to step S102.

At step S102, the camera controller 21 is used to perform processing toset the aperture value of the optical system (F-value) at the aperturevalue for focus detection. Specifically, the camera controller 21,first, receives the limit value of the opening side of the aperturevalue of the optical system at the time of detection of the focus stateof the optical system as the opening side limit value from the lenscontroller 37 and acquires the limit value of the closing side of theaperture value of the optical system at the time of detection of thefocus state of the optical system as the closing side limit value fromthe memory 29. Note that, in the present embodiment, the opening sidelimit value is stored as the number of closing steps from the openaperture value in the memory 39, so the camera controller 21 uses theopen aperture value and the number of closing steps from the openaperture value as the basis to find the limit value of the opening side(F-value) of the aperture value of the optical system at the time offocus detection as the opening side limit value.

Further, the camera controller 21 uses the acquired opening side limitvalue and closing side limit value as the basis to set the aperturevalue of the optical system for focus detection. Specifically, thecamera controller 21 sets the aperture value of the optical system atthe closing side limit value when the capture aperture value which isset for capturing an image is a value at the closing side from theclosing side limit value. Here, FIG. 10 is a view which shows an exampleof the relationship between the aperture value which is set for focusdetection and the capture aperture value. Note that, the example whichis shown in FIG. 10 shows a lens barrel 3 with an open aperture value ofF1.2 and a maximum aperture value (maximum F-value) of F16 where theopening side limit value is acquired as F2.8 and the closing side limitvalue is acquired as F5.6. For example, in the example which is shown inFIG. 10A, the capture aperture value is set to F16 and the captureaperture value F16 is a value at the closing side from the closing sidelimit value F5.6, so the camera controller 21 sets the aperture value ofthe optical system at the closing side limit value F5.6. Further, in theexample which is shown in FIG. 10B, the capture aperture value is F8, soin the same way as FIG. 10A, the camera controller 21 sets the aperturevalue of the optical system at the closing side limit value F5.6.

Further, the camera controller 21 sets the aperture value of the opticalsystem at the capture aperture value when the capture aperture valuewhich was set for capturing an image is a value the same as the closingside limit value or a value at the opening side from the closing sidelimit value. For example, in the example which is shown in FIG. 10C, thecapture aperture value is the same F5.6 as the closing side limit value,so the camera controller 21 sets the aperture value of the opticalsystem at the capture aperture value F5.6. Further, in the example whichis shown in FIG. 10D, the capture aperture value is set at F4 and thecapture aperture value F4 is a value at the opening side from theclosing side limit value F5.6, so the camera controller 21 sets theaperture value of the optical system at the capture aperture value F4.Similarly, in the examples which are shown in FIGS. 10E to 10G as well,in the same way as in FIG. 10D, the capture aperture value is a value atthe opening side from the closing side limit value, so the cameracontroller 21 sets the aperture value of the optical system at thecapture aperture value.

At step S103, a through-the-lens image is generated by the cameracontroller 21 and the through-the-lens image is displayed by theelectronic viewfinder 26 of the viewing optical system. Specifically,the image pickup device 22 is used for an exposure operation and thecamera controller 21 is used to read the pixel data of the capturepixels 221. Further, the camera controller 21 uses the read pixel dataas the basis to generate a through-the-lens image. The generatedthrough-the-lens image is sent to the liquid crystal drive circuit 25and is displayed at the electronic viewfinder 26 of the viewing opticalsystem. Further, due to this, it is possible for a user to visuallyconfirm the moving image of the object through the eyepiece 27.

At step S104, the camera controller 21 is used to split the capturedpicture into a plurality of regions and measure the light for each splitregion, that is, perform multi-pattern photometry, and calculate thebrightness value By of the captured picture as a whole. Further, thecamera controller 21 uses the calculated brightness value By of thecaptured picture as a whole as the basis to change at least one of thelight receiving sensitivity Sv and exposure time Tv so that a suitableexposure is obtained at the captured picture as a whole. Note that, atstep S104, the aperture Av corresponding to the aperture value which wasset at step S102 is left fixed while at least one of the light receivingsensitivity Sv and exposure time Tv is changed. Further, the changedlight receiving sensitivity Sv and exposure time Tv are used as thebasis to, for example, set the shutter speed of the shutter 23, thesensitivity of the image pickup device 22, etc. so as to control theexposure of the image pickup device 22.

At step S105, the camera controller 21 is used to judge if suitableexposure is obtained at the captured picture as a whole by the exposurecontrol of step S104. When changing just the light receiving sensitivitySv and or exposure time Tv is not enough to obtain suitable exposure ofthe captured picture as a whole, the routine proceeds to step S106,while when changing just one of the light receiving sensitivity Sv andexposure time Tv is enough to obtain suitable exposure of the capturedpicture as a whole, the routine proceeds to step S108.

At step S106, since it is judged that just change of the light receivingsensitivity Sv and exposure time Tv is not enough to obtain suitableexposure at the captured picture as a whole, the camera controller 21 isused to change the aperture Av. Specifically, the camera controller 21uses the brightness value By of the captured picture as a whole as thebasis to change the aperture Av so that the aperture value of theoptical system becomes in a range between the opening side limit valueand the closing side limit value when the capture aperture value is avalue at the closing side from the closing side limit value. Forexample, in the example which is shown in FIG. 10A, the capture aperturevalue F16 is a value at the closing side from the closing side limitvalue F5.6, so the camera controller 21 changes the aperture Av so thatthe aperture value of the optical system becomes in the range from theopening side limit value F2.6 to the closing side limit value F5.6 andperforms exposure control so that suitable exposure is obtained at thecaptured picture as a whole. The same is true for the example which isshown in FIG. 10B.

Further, the camera controller 21 uses the brightness value By of thecaptured picture as a whole as the basis to change the aperture Av sothat the aperture value of the optical system becomes in a range betweenthe opening side limit value and the capture aperture value when thecapture aperture value is a value the same as the closing side limitvalue or a value at the opening side from the closing side limit value.For example, in the example which is shown in FIG. 10C, the captureaperture value F5.6 is a value the same as the closing side limit valueF5.6, so the camera controller 21 changes the aperture Av so that theaperture value of the optical system becomes one in a range from theopening side limit value F2.6 to the capture aperture value F5.6.Further, in the example which is shown in FIG. 10D, the capture aperturevalue F4 is a value at the opening side from the closing side limitvalue F5.6, so the camera controller 21 changes the aperture Av so thatthe aperture value of the optical system becomes one in a range from theopening side limit value F2.6 to the capture aperture value F4.

Note that, when the capture aperture value is the same value as theopening side limit value or a value at the opening side from the openingside limit value, the camera controller 21 leaves the aperture value ofthe optical system as the capture aperture value. For example, in theexample which is shown in FIG. 10E, the capture aperture value F2.6 is avalue the same as the opening side limit value F2.6, so the cameracontroller 21 leaves the aperture value of the optical system as thecapture aperture value F2.6. The same is true in the examples which areshown in FIGS. 10F to 10G as well. Further, in the present embodiment,when it is possible to change the aperture Av within the range of apredetermined aperture value, the camera controller 21, for example, asshown in FIGS. 10A to 10D, changes the aperture Av to the opening sidewith some margin so that it is not necessary to again change theaperture Av even when the brightness value By of the captured picture asa whole again changes.

At step S107, the camera controller 21 is used to determine the lightreceiving sensitivity Sv and exposure time Tv so that suitable exposureis obtained at the captured picture as a whole by the aperture Av whichwas changed at step S106. Specifically, the camera controller 21, in thesame way as step S104, measures the light at the captured picture as awhole by multi-pattern photometry and calculates the brightness value Byof the captured picture as a whole. Further, the camera controller 21uses the calculated brightness value By and the aperture Av which waschanged at step S106 as the basis to determine the light receivingsensitivity Sv and exposure time Tv giving suitable exposure at thecaptured picture as a whole and uses the determined light receivingsensitivity Sv and exposure time Tv and the aperture Av which waschanged at step S106 as the basis to control exposure for the imagepickup device 22.

Further, at step S108, the camera controller 21 is used to performprocessing to calculate the amount of defocus by the phase differencedetection system. Specifically, first, the image pickup device 22 isused to receive the light beam from the optical system, then the cameracontroller 21 is used to read the pair of image data corresponding tothe pair of images from the focus detection pixels 222 a and 222 b whichfaun the three focus detection pixel strings 22 a to 22 c of the imagepickup device 22. In this case, a configuration is also possible wherewhen, due to manual operation of the photographer, a specific focusdetection position is selected, only the data from the focus detectionpixels corresponding to that focus detection position is read out.Further, the camera controller 21 uses the read pair of image data asthe basis to perform image deviation detection processing (correlationprocessing), calculates the shift amount at the focus detectionpositions corresponding to the three focus detection pixel strings 22 ato 22 c, and, furthermore, converts the shift amount to an amount ofdefocus. Further, the camera controller 21 evaluates the reliability ofthe calculated amount of defocus. For example, the camera controller 21uses the degree of match or contrast etc. of the pair of image data asthe basis to judge the reliability of the amount of defocus.

At step S109, the camera controller 21 is used to judge if the shutterrelease button which was provided at the operating unit 28 was halfpressed (first switch SW1 on) or not. When the shutter release buttonwas half pressed, the routine proceeds to step S110, while when theshutter release button was not half pressed, the routine returns to stepS103 and the display of the through-the-lens image, exposure control,and calculation of the amount of defocus are repeatedly performed untilthe shutter release button is half pressed.

At step S110, the camera controller 21 is used to judge if the amount ofdefocus could be calculated by the phase difference detection system.When the amount of defocus could be calculated, it is judged that thedistance could be measured and the routine proceeds to step S111, whilewhen the amount of defocus could not be calculated, it is judged thatthe distance could not be measured and the routine proceeds to stepS115. Note that, in the present embodiment, even when it is possible tocalculate the amount of defocus, if the reliability of the calculatedamount of defocus is low, it is treated as if the amount of defocuscould not be calculated and the routine proceeds to step S115. In thepresent embodiment, for example, when the contrast of the object is low,when the object is an ultra low brightness object, when the object is anultra high brightness object, etc., it is judged that the reliability ofthe amount of defocus is low.

At step S111, the camera controller 21 uses the amount of defocus whenwas calculated at step S108 as the basis to calculate the amount ofdrive of the lens which is required for driving the focus lens 32 to thefocal position and send the calculated lens drive amount through thelens controller 37 to the focus lens drive motor 36. Due to this, thefocus lens drive motor 36 is used to drive the focus lens 32 based onthe calculated lens drive amount.

At step S112, the camera controller 21 is used to judge if the shutterrelease button has been full pressed (second switch SW2 on). When thesecond switch SW2 is on, the routine proceeds to step S113, while whenthe second switch SW2 is not on, the routine returns to step S103.

At step S113, to capture the image, the camera controller 21 is used toperform processing which sets the aperture value of the optical systemat the capture aperture value. For example, in the example which isshown in FIG. 10A, for capturing the image, the camera controller 21changes the aperture value of the optical system from the aperture valueat the time of focus detection (in the range from the opening side limitvalue F2.8 to the closing side limit value F5.6) to the capture aperturevalue F16. In the same way, in the examples which are shown in FIGS. 10Bto 10G as well, the aperture value of the optical system is changed fromthe aperture value for focus detection to the capture aperture value forcapturing the image. Further, at the following step S114, the imagepickup device 22 is used to capture the image by the aperture valuewhich was set at step S113, and the captured image data of the image isstored in the memory 24.

On the other hand, when it was judged at step S110 that the amount ofdefocus could not be calculated, the routine proceeds to step S115 forexposure suitable for focus detection. At step S115, the cameracontroller 21 is used for exposure control for focus detection so thatexposure suitable for focus detection is obtained. Specifically, thecamera controller 21 uses the output of the image pickup device 22 asthe basis to measure the light by spot photometry in predeterminedregions including the focus detection areas (focus detection pixelstrings 22 a, 22 b, and 22 c shown in FIG. 2) and to calculate thebrightness values SpotBv in predetermined regions including the focusdetection areas. Further, the camera controller 21 uses the calculatedbrightness values SpotBv as the basis to determine the light receivingsensitivity Sv, exposure time Tv, and aperture Av so that exposuresuitable for focus detection (for example, exposure one step brighterthan suitable exposure) is obtained. Note that, in the exposure controlfor focus detection of step S115, in the same way as steps S104 to S107as well, the camera controller 21 changes the light receivingsensitivity Sv and the exposure time Tv with priority. Only when justchange of the light receiving sensitivity Sv and the exposure time Tv isnot enough to obtain exposure suitable for focus detection, the openingside limit value and closing side limit value which were acquired atstep S102 are used as the basis to change the aperture Av. That is,using the camera controller 21, as shown in the examples which are shownin FIGS. 10A to 10B, when the capture aperture value is a value at theclosing side from the closing side limit value, the brightness valuesSpotBv in predetermined regions including the focus detection areas areused as the basis to change the aperture Av so that the aperture valueof the optical system becomes in a range between the opening side limitvalue and the closing side limit value. Further, as shown in FIGS. 10Cto 10D, when the capture aperture value is a value the same as theclosing side limit value or a value at the opening side from the closingside limit value, the brightness values SpotBv in predetermined regionsincluding the focus detection areas are used as the basis to change theaperture value Av so that the aperture value of the optical systembecomes in a range between the opening side limit value and the captureaperture value. Furthermore, as shown in FIGS. 10E to 10G, when thecapture aperture value is the same value as the opening side limit valueor a value at the opening side from the opening side limit value, theaperture value of the optical system is left as the capture aperturevalue.

At step S116, the camera controller 21 uses the image data which wasobtained by exposure suitable for focus detection as the basis tocalculate the amount of defocus. At the following step S117, the cameracontroller 21 uses the image data which was obtained by exposuresuitable for focus detection as the basis to judge if the amount ofdefocus could be calculated. When the amount of defocus could becalculated, the routine proceeds to step S111 where the calculatedamount of defocus is used as the basis for processing for driving thefocus lens 32. On the other hand, when the amount of defocus could notbe calculated even when using the image data which was obtained byexposure suitable for focus detection, the routine proceeds to step S118where the later explained scan operation processing is performed. Notethat, at step S117 as well, in the same way as step S110, even when theamount of defocus could be calculated, when the reliability of thecalculated amount of defocus is low, it is treated as if the amount ofdefocus could not be calculated.

At step S118, the camera controller 21 is used to perform scan operationprocessing for performing a scan operation. Here, the “scan operation”is an operation using the focus lens drive motor 36 to drive the focuslens 32 for scanning while using the camera controller 21 to calculatethe amount of defocus by the phase difference detection system andcalculate the focal evaluation value at the same time at a predeterminedinterval and, due to this, detecting the focal position by the phasedifference detection system and detecting the focal position by thecontrast detection system at the same time at a predetermined interval.Below, referring to FIG. 11, scan operation processing according to thepresent embodiment will be explained. Note that, FIG. 11 is a flow chartfor the scan operation processing according to the present embodiment.

First, at step S201, the camera controller 21 is used to performprocessing for starting the scan operation. Specifically, the cameracontroller 21 sends the lens controller 37 a scan drive statsinstruction, whereupon the lens controller 37 uses the instruction fromthe camera controller 21 as the basis to drive the focus lens drivemotor 36 and drive the focus lens 32 along the optical axis L1 forscanning. Note that, the direction for drive for scanning is notparticularly limited. It is also possible to perform the scan drive ofthe focus lens 32 from the infinite end to the near end or to perform itfrom the near end to the infinite end.

Further, the camera controller 21 drives the focus lens 32 while readingpairs of image data corresponding to pairs of images from the focusdetection pixels 222 a and 222 b of the image pickup device 22 atpredetermined intervals, uses this as the basis to calculate the amountof defocus by the phase difference detection system and evaluate thereliability of the amount of defocus calculated, drives the focus lens32 while reading the pixel outputs from the capture pixels 221 of theimage pickup device 22 at predetermined intervals, uses this as thebasis to calculate a focal evaluation value, and thereby acquires focalevaluation values at different focus lens positions so as to detect thefocal position by the contrast detection system.

At step S202, the camera controller 21 is used to perform a scanoperation and judge as a result if the amount of defocus could becalculated by the phase difference detection system. When the amount ofdefocus could be calculated, it is judged that the distance could bemeasured and the routine proceeds to step S205, while when the amount ofdefocus could not be calculated, it is judged that the distance couldnot be calculated and the routine proceeds to step S203.

At step S203, the camera controller 21 is used to perform a scanoperation and judge as a result if the focal position could be detectedby the contrast detection system. When the focal position could bedetected by the contrast detection system, the routine proceeds to stepS207, while when the focal position could not be detected, the routineproceeds to step S204.

At step S204, the camera controller 21 is used to judge if the scanoperation was performed for the entire region of the drivable range ofthe focus lens 32. When the scan operation could not be performed forthe entire region of the drivable range of the focus lens 32, theroutine returns to step S202 where steps S202 to S204 are repeated so asto perform a scan operation, that is, drive the focus lens 32 forscanning while calculating the amount of defocus by the phase differencedetection system and detect the focal position by the contrast detectionsystem at the same time at predetermined intervals. On the other hand,when the scan operation has been finished for the entire region of therange of drivability of the focus lens 32, the routine proceeds to stepS208.

Further, when, as a result of performance of the scan operation, it isjudged at step S202 that the phase difference detection system can beused to calculate the amount of defocus, the routine proceeds to stepS205. At step S205, a focusing operation is performed based on theamount of defocus which was calculated by the phase difference detectionsystem.

That is, at step S205, the camera controller 21 is used for processingto stop the scan operation, then the calculated amount of defocus isused to calculate the amount of drive of the lens which is required fordriving the focus lens 32 to the focal position and the calculated lensdrive amount is sent through the lens controller 37 to the lens drivemotor 36. Further, the lens drive motor 36 uses the lens drive amountwhich was calculated by the camera controller 21 as the basis to drivethe focus lens 32 to the focal position. When the drive operation of thefocus lens 32 to the focal position is completed, the routine proceedsto step S206. At step S206, the camera controller 21 is used to judgefocus.

Further, when, as a result of the scan operation, at step S203, it isjudged that the contrast detection system can be used to detect thefocal position, the routine proceeds to step S207 where a driveoperation of the focus lens 32 is performed based on the focal positionwhich was detected by the contrast detection system.

That is, the camera controller 21 is used to perform processing to stopthe scan operation, then the focal position which was detected by thecontrast detection system is used as the basis to perform lens driveprocessing to drive the focus lens 32 to the focal position. Further,when the drive operation of the focus lens 32 to the focal position isfinished, the routine proceeds to step S206 where the camera controller21 is used to judge focus.

On the other hand, when, at step S204, it is judged that the scanoperation has finished for the entire region of the drivable range ofthe focus lens 32, the routine proceeds to step S208. At step S208,processing is performed to end the scan operation since the result ofthe scan operation shows that focus detection is not possible by eitherthe phase difference detection system or the contrast detection system.Next, the routine proceeds to step S209 where the camera controller 21is used to judge that focusing is not possible.

Further, after the scan operation processing of step S118 ends, theroutine proceeds to step S119 where the camera controller 21 uses theresult of focus judgment of the scan operation processing as the basisto judge if focusing was possible. When it is judged that focusing waspossible in the scan operation processing (step S206), the routineproceeds to step S112. On the other hand, when it is judged thatfocusing was not possible (step S209), the routine proceeds to stepS120. At step S120, the fact of focusing being impossible is displayed.The fact of focusing being impossible is displayed by, for example, theelectronic viewfinder 26.

Note that, when it is judged at step S101 that a moving image is beingcaptured, the routine proceeds to step S121. At step S121, the cameracontroller 21 is used for exposure control so as to obtain exposuresuitable for capturing a moving image. Specifically, the cameracontroller 21 gives priority to the appearance of the moving image, someasures the light by multi-pattern photometry so as to calculate thebrightness value By of the captured picture as a whole and uses thecalculated brightness value By as the basis to determine the lightreceiving sensitivity Sv and exposure time Tv so that suitable exposureis obtained at the captured picture as a whole. In particular, duringcapture of a moving image, the aperture Av is left fixed and only thelight receiving sensitivity Sv and exposure time Tv are changed forexposure control.

Further, at step S122, the camera controller 21 is used to detect thefocus state of the optical system and to adjust the focus by the focuslens 32 in accordance with the detected focus state. Specifically, thecamera controller 21 uses the captured image data as the basis tocalculate the amount of defocus and judge if the amount of defocus couldbe calculated at steps S111 and S115 to S120. Further, when the amountof defocus was calculated, the calculated amount of defocus is used asthe basis to drive the focus lens 32, while when the amount of defocuswas not calculated, the scan operation processing is performed. Further,the routine proceeds to step S123 where the image pickup device 22 isused to capture the moving image. The image data of the moving imagewhich is captured by the camera controller 21 is stored in the memory24.

In the above way, in the present embodiment, the limit value of theopening side of the aperture value of the optical system at the time offocus detection is stored as the opening side limit value in the lensbarrel 3. Further, the limit value of the closing side of the aperturevalue of the optical system at the time of focus detection is stored asthe closing side limit value in the camera body 2. Further, the cameracontroller 21 uses the opening side limit value which was received fromthe lens barrel 3 and the closing side limit value which was acquiredfrom the memory 29 as the basis to set the aperture value of the opticalsystem at the time of focus detection. Specifically, when the captureaperture value at the time of capturing the image is a value at theclosing side from the closing side limit value, the aperture value ofthe optical system at the time of focus detection is set in a rangebetween the opening side limit value and the closing side limit value.In this way, in the present embodiment, by limiting the aperture valueof the optical system at the time of focus detection to a value at theclosing side from the opening side limit value, even when changing theaperture value of the optical system from the aperture value at the timeof focus detection to the capture aperture value for capturing an imageso as to capture an image, the amount of movement of the image plane ofthe optical system accompanying a change of the aperture value of theoptical system can be made a predetermined amount or less. As a result,it is possible to make the focus position which was detected at the timeof focus detection within the range of the depth of field of the opticalsystem at the time of capture of an image and possible to capture animage focused on an object.

Further, in the present embodiment, when the aperture value at the timeof capture of an image is a value at the closing side from the closingside limit value, by limiting the aperture value of the optical systemat the time of focus detection to a value at the opening side from theclosing side limit value, it is possible to effectively prevent theoccurrence of vignetting at the time of focus detection and possible tosuitably detect the focus state of the optical system. Furthermore, inthe present embodiment, when the capture aperture value is a value atthe opening side from the closing side limit value, by setting theaperture value of the optical system at the time of focus detectionwithin a range between the opening side limit value and the captureaperture value, it is possible to limit the aperture value of theoptical system at the time of focus detection so as not to become avalue at the closing side from the capture aperture value. Due to this,when capturing an image, the depth of field at the time of capture ofthe image ends up becoming shallower than the depth of field at the timeof focus detection. At the time of capture of the image, it is possibleto effectively prevent an object focused at the time of focus detectionfrom ending up deviating from the depth of field of the optical system.As a result, it is possible to capture an image focused on an objectwell.

Second Embodiment

Next, a second embodiment of the present invention will be explainedbased on the drawings. The camera la according to the second embodiment,as shown in FIG. 12, has a configuration similar to the camera 1according to the first embodiment except for the fact that the lensbarrel 3 a is mounted to the camera body 2 through a lens adapter 5 andperforms a similar operation to the camera 1 according to the firstembodiment except for the points explained below.

That is, the camera 1 a according to the second embodiment can mount thelens barrel 3 a at the camera body 2 through the lens adapter 5. Here,the lens barrel 3 a has a configuration similar to the lens barrel 3 ofthe first embodiment except for the fact that it does not store theopening side limit value in the memory 39. Further, in the secondembodiment, for example, by the lens barrel 3 a being mounted at thecamera body 2 through the lens adapter 5, the adapter controller 51sends the camera controller 21 and lens controller 37 a signal whichshows that the lens adapter 5 has been mounted. Due to this, it ispossible to transfer the aperture value of the optical system and otherinformation between the lens controller 37 and the camera controller 21through an electrical signal contact 41 which is provided at the mount 4and an electrical signal contact 61 which is provided at the mount 6.

Next, an example of the operation of the camera la according to thesecond embodiment will be explained with reference to FIG. 13. FIG. 13is a view which shows an example of the relationship between theaperture value which is set at the time of focus detection and thecapture aperture value in the second embodiment. Further, the examplewhich is shown in FIG. 13 shows the situation where the open aperturevalue is F1.2 and the maximum aperture value (maximum F-value) is F16and the camera controller 21 is used for exposure control in focusdetection based on only the closing side limit value without using theopening side limit value.

In the second embodiment, when the capture aperture value for capturingan image is a value at the closing side from the closing side limitvalue, the camera controller 21 sets the aperture value of the opticalsystem at the closing side limit value for focus detection and then setsthe aperture value of the optical system at the capture aperture valuefor image capture. For example, in the example which is shown in FIG.13A, the capture aperture value is F16 and the capture aperture value isthe value at the closing side from the closing side limit value F5.6, sothe aperture value of the optical system is set at the closing sidelimit value F5.6 for focus detection. Further, when capturing an image,the aperture value of the optical system is changed from the closingside limit value F5.6 to the capture aperture value F16 for capture ofthe image. In the same way, in the example which is shown in FIG. 13B aswell, the capture aperture value F8 is a value at the closing side fromthe closing side limit value F5.6, the focus detection is performed by aclosing side limit value F5.6, and the image is captured by the captureaperture value F8.

Further, when the capture aperture value is a value the same as theclosing side limit value or a value at the opening side from the closingside limit value, the camera controller 21 sets the aperture value ofthe optical system at the capture aperture value for focus detectionand, further, leaves the aperture value of the optical system set at thecapture aperture value for capture of an image. For example, in theexample which is shown in FIG. 13C, the capture aperture value is thesame F5.6 as the closing side limit value, so the camera controller 21sets the aperture value of the optical system at the capture aperturevalue F5.6 for focus detection and, further, leaves the capture aperturevalue F5.6 as is for capture of the image. Further, in the example whichis shown in FIG. 13D, the capture aperture value is F4 and the captureaperture value is a value at the opening side from the closing sidelimit value F5.6, so the camera controller 21 sets the aperture value ofthe optical system at the capture aperture value F4 for focus detectionand, further, leaves the set capture aperture value as is for capture ofthe image. The same is true in the examples of the situations which areshown in FIGS. 13E and 13F.

In the above way, in the second embodiment, when not acquiring theopening side limit value from the lens controller 37, when the captureaperture value is a value the same as the closing side limit value or avalue at the opening side from the closing side limit value, as shown inFIGS. 13C to 13F, the aperture value of the optical system is set to thecapture aperture value for focus detection and, further, is left set atcapture aperture value for capture of the image. Due to this, in thepresent embodiment, from the time of focus detection to the time ofcapture of an image, the aperture value of the optical system is notchanged, so the position of the image plane of the optical system is notchanged at the time of focus detection and at the time of capture of animage. The focal position which was detected in the focus detectionbecomes within the range of the depth of field of the optical system atthe time of capture of an image and an image which is focused at theobject can be captured.

Third Embodiment

Next, a third embodiment of the present invention will be explainedbased on the drawings. In the third embodiment, in the camera 1 which isshown in FIG. 1, a similar operation is performed as in the camera 1according to the first embodiment except for using the later explainedvariable amount of the aperture value as the basis to control theaperture value at the time of focus detection.

In the third embodiment, the lens controller 37, as shown in FIG. 14,stores the range of aperture values which can be set as the aperturevalue of the optical system at the time of focus detection in the memory39 as the variable amount of the aperture value from the captureaperture value. Here, for the image capture after focus detection, whenchanging the aperture value of the optical system from, for example, theaperture value F1.4 at the time of focus detection to the captureaperture value F2 for image capture, sometimes movement of the imageplane accompanying a change of the aperture value causes the focalposition which was detected at the time of focus detection to end updeviating from the depth of field of the optical system at the time ofcapture of the image and an image focused at the object at the time offocus detection cannot be captured. In particular, the more to theopening side the aperture value of the optical system, this trendbecomes greater. In such a case, by making the aperture value of theoptical system at the time of focus detection not F1.4, but, forexample, as shown in FIG. 14, F1.6 closer to the capture aperture valuethan F1.4, sometimes it is possible to suppress the amount of movementof the image plane accompanying change of the aperture value andpossible to capture an image focused on the object. For example, in theexample which is shown in FIG. 14, the aperture value at the time offocus detection can be set to the range of F1.6 to F5.6 so that theamount of movement of the image plane accompanying change of theaperture value in this way becomes a predetermined amount enabling goodcapture of the image or less. In this case, the memory 39 stores thenumber of closing step 2/3 for making the capture aperture value F2 theaperture value F1.6 as the variable amount of the aperture value at theopening side from the capture aperture value and stores the number ofclosing steps 3 for making the capture aperture value F2 the aperturevalue F5.6 as the variable amount of the aperture value at the closingside from the capture aperture value. In this way, the variable amountof the aperture value expresses as the number of closing steps theamount of the aperture value by which the aperture value of the opticalsystem can be changed from the capture aperture value at the time offocus detection.

Note that, the variable amount of the aperture value differs for eachcapture aperture value. The memory 39 stores the variable amount of theaperture value for each capture aperture value. Further, as shown inFIG. 14, if comparing the variable amount of the aperture value at theopening side and the variable amount of the aperture value at theclosing side, the variable amount of the aperture value at the openingside tends to become smaller than the variable amount of the aperturevalue at the closing side. This is because, as explained above, the moreto the opening side the aperture value of the optical system, thegreater the movement of the image plane accompanying a change of theaperture value tends to become.

The camera controller 21 acquires the variable amount of the aperturevalue corresponding to the current capture aperture value from the lenscontroller 37 and uses the acquired variable amount of the aperturevalue as the basis to set the aperture value at the time of focusdetection. Note that, the method of control of the aperture value at thetime of focus detection will be explained later.

Next, an example of the operation of the camera 1 according to the thirdembodiment will be explained. FIG. 15 is a flow chart which shows anexample of operation of the camera 1 according to the presentembodiment. Note that, the following operation is started by the powerof the camera 1 being turned on.

As shown in FIG. 15, first, at step S301, the camera controller 21 isused to acquire the current capture aperture value. Further, at stepS302, the camera controller 21 is used to acquire a variable amount ofthe aperture value corresponding to the current capture aperture valuewhich is acquired at step S301. Here, the variable amount of theaperture value is stored for each capture aperture value in the memory39 of the lens barrel 3. For this reason, the camera controller 21acquires the variable amount of the aperture value corresponding to thecapture aperture value from the memory 39 through the lens controller37.

For example, as shown in FIG. 14, to make the amount of movement of theimage plane accompanying a change of the aperture value a predeterminedamount enabling the image to be captured well or less, when the aperturevalue of the optical system at the time of focus detection can be setfor example, in the range of F1.6 to F5.8 corresponding to the captureaperture value F2, the number of closing step 2/3 for making the captureaperture value F2 the aperture value F1.6 is acquired as the variableamount of the aperture value at the opening side, while the number ofclosing steps 3 for making the capture aperture value F2 the aperturevalue F5.8 is acquired from the memory 39 as the variable amount of theaperture value at the closing side.

At step S303, the camera controller 21 is used to judge if the shutterrelease button which is provided at the operating unit 28 is halfpressed (first switch SW1 on). When the shutter release button is halfpressed, the routine proceeds to step S304. On the other hand, when theshutter release button is not half pressed, the routine proceeds to stepS301. Until the shutter release button is half pressed, the acquisitionof the capture aperture value and the acquisition of the variable amountof the aperture value corresponding to the acquired capture aperturevalue are repeatedly performed.

At step S304, the camera controller 21 uses at the variable amount ofthe aperture value which was acquired at step S302 as the basis to setthe aperture value of the optical system. Specifically, the cameracontroller 21 sets the aperture value of the optical system for focusdetection in the range of the variable amount of the aperture value fromthe capture aperture value. For example, as shown in FIG. 14, when,corresponding to the capture aperture value F2, 2/3 step is acquired asthe variable amount of the aperture value at the opening side and 3steps are acquired as the variable amount of the aperture value at theclosing side, the camera controller 21 can set the aperture value of theoptical system to become an aperture value suitable for focus detectionin the range between the aperture value F1.6 opened by a 2/3 step to theopening side from the capture aperture value F2 and the aperture valueF5.8 closed by 3 steps to the closing side from the capture aperturevalue F2, that is, in the range from F1.6 to F5.8. For example, when thebrightness of the object is low, the camera controller 21 can set theaperture value of the optical system at an aperture value at the openingside in F1.6 to F5.8. Further, when broadening the range of detection atthe time of focus detection in the optical axis direction, it ispossible to set the aperture value of the optical system at the aperturevalue at the closing side in F1.6 to F5.8.

At steps S305 to S307, in the same way as steps S115, S116, and S111 ofthe first embodiment, after the exposure control for focus detection,the amount of defocus is calculated. The drive operation of the focuslens 32 is started based on the calculated amount of defocus.

Further, at steps S308 to S310, in the same way as steps S112 to S114 ofthe first embodiment, it is judged if the shutter release button is fullpressed (second switch SW2 on). When the second switch SW2 is on, theaperture value of the optical system is set at the capture aperturevalue, then the image pickup device 22 is used for capture of the image,and the image data of the captured image is stored in the memory 24.Note that, when the second switch SW2 is not on, the routine returns tostep S301.

As explained above, in the third embodiment, as shown in FIG. 14, at thetime of focus detection, the range of the aperture value which can beset as the aperture value of the optical system is stored in the memory39 of the lens barrel 3 as the variable amount of the aperture valuefrom the capture aperture value, that is, the variable amount of theaperture value. The camera controller 21 acquires the variable amount ofthe aperture value corresponding to the current capture aperture valuefrom the lens barrel 3 and sets the aperture value of the optical systemat the time of focus detection, as shown in FIG. 14, to the range of thevariable amount of the aperture value with respect to the currentcapture aperture value. In this way, by setting the aperture value ofthe optical system at the time of focus detection within the range ofthe variable amount of the aperture value with respect to the captureaperture value, even if changing the aperture value of the opticalsystem from the aperture value at the time of focus detection to thecapture aperture value, it is possible to make the amount of movement ofthe image plane accompanying a change of the aperture value apredetermined amount or less and as a result it is possible to make thefocal position which was detected by the focus detection within a rangeof the depth of field of the optical system at the time of capture of animage and to capture an image focused on the object.

Note that, in the third embodiment, as shown in FIG. 14, theconfiguration was shown in which the variable amount of the aperturevalue is set to the opening side and closing side from the captureaperture value, but as shown in FIG. 16, the variable amount of theaperture value may also be set to just the opening side from the captureaperture value. For example, in the example which is shown in FIG. 16,the camera controller 21 can set the aperture value of the opticalsystem to become an aperture value suitable for focus detection in therange between the aperture value F1.6 opened by 2/3 step at the openingside from the capture aperture value F2 and the capture aperture valueF2. Note that, FIG. 16 is a view for explaining another example of thevariable amount of the aperture value.

Fourth Embodiment

Next, a fourth embodiment of the present invention will be explainedwith reference to the drawings. The camera 1 b according to the fourthembodiment, as shown in FIG. 17, has a configuration similar to thecamera 1 according to the first embodiment other than the lens barrel 3being mounted at the camera body 2 through the lens adapter 5 a. Itoperates in the same way as the camera 1 according to the firstembodiment other than on the points explained below.

FIG. 17 is a view of the configuration of principal parts which show acamera 1 b according to the fourth embodiment. The camera 1 b of thefourth embodiment is comprised of a camera body 2, lens barrel 3, andlens adapter 5 a. The camera body 2 and the lens barrel 3 are detachablycoupled through a lens adapter 5 a.

In the fourth embodiment, as shown in FIG. 17, between the lens barrel 3and the camera body 2, a lens adapter 5 a is interposed for mounting thelens barrel 3 at the camera body 2. The adapter controller 51 receiveslens information from the lens controller 37 through an electricalsignal contact 51 which is provided at the mount 6 and sends the lenscontroller 37 the amount of defocus, aperture size, and otherinformation which it received from the camera controller 21. Further,the adapter controller 51 receives the amount of defocus, aperture size,or other information from the camera controller 21 through theelectrical signal contact 41 which is provided at the mount 4 and sendsthe lens information which was received from the lens controller 37 tothe camera controller 21. In this way, in the present embodiment, lensinformation etc. are transferred between the camera controller 21 andthe lens controller 37 through the lens adapter 5 a.

The memory 52 of the lens adapter 5 a stores in advance as the openingside limit value the limit value of the opening side of the aperturevalue of the optical system at the time of detection of the focus stateof the optical system. Here, for example, when making the aperture valueat the time of detection of the focus state of the optical system F1.4and making the aperture value at the time of capture of an image F2.8,if changing the aperture value of the optical system from the aperturevalue F1.4 at the time of focus detection to the capture aperture valueF2.8 for performing the image capture after focus detection, sometimesmovement of the image plane accompanying a change of the aperture valuecauses the focus position which was detected at the time of focusdetection to end up deviating from the depth of field of the opticalsystem at the time of capture of the image and it is not possible tocapture a focused object for an object focused at the time of focusdetection. In particular, the more to the opening side the aperturevalue of the optical system, the greater this trend. Therefore, in thiscase, for example, by limiting the aperture value at the opening side atthe time of detection of the focus state of the optical system not atF1.4, but up to F2, it is possible to suppress the amount of movement ofthe image plane accompanying a change of the aperture value. Even whenchanging the aperture value of the optical system from the aperturevalue at the time of detection of the focus state to the captureaperture value, it is possible to capture an image focused on theobject. The opening side limit value, in this way, is the limit value ofthe opening side of the aperture value of the optical system whichenables an image to be captured well even when changing the aperturevalue of the optical system from the aperture value at the time of focusdetection to the capture aperture value and becomes a valuecorresponding to the lens barrel 3 and unique to the lens barrel 3.

In the present embodiment, the opening side limit value is stored fromthe memory 52 of the lens adapter 5 a for each type of the lens barrel3. The adapter controller 51 uses the lens information which wasreceived from the lens barrel 3 as the basis to identify the type of thelens barrel 3 and thereby acquires the opening side limit valuecorresponding to the type of the lens barrel 3. Further, the adaptercontroller 51 sends the opening side limit value which was acquiredcorresponding to the type of the lens barrel 3 from the adaptercontroller 51 to the camera controller 21. Note that, the adaptercontroller 51 acquires the predetermined opening side limit value whichis stored in the memory 52 and sends the acquired predetermined openingside limit value to the camera controller 21 when it is not possible toidentify the type of the lens barrel 3.

Further, the opening side limit value is stored in the memory 52 as thenumber of closing steps from the open aperture value. For example, whenthe opening side limit value is an aperture value (F-value) of F2, ifthe open aperture value is F1.2 and the number of closing steps of theaperture 34 for changing the aperture value of the optical system fromthe open aperture value F1.2 to the opening side limit value F2 is 2steps, the adapter controller 51 stores the opening side limit value as2 steps. In this way, by storing the opening side limit value as thenumber of closing steps from the open aperture value, for example, evenwhen the lens position of the zoom lens is changed, it is possible touse the open aperture value corresponding to the lens position of thezoom lens as the basis to find the opening side limit valuecorresponding to the lens position of the zoom lens. There is no need tostore the open aperture value for each lens position of the zoom lens.Note that, the above-mentioned open aperture value, opening side limitvalue, and number of closing steps are examples. The invention is notlimited to these values.

Next, an example of the operation of the camera 1 b according to thefourth embodiment will be explained. FIG. 18 is a flow chart which showsan example of the operation of the camera 1 b according to the fourthembodiment. Note that, the following operation is started by the powerof the camera 1 b being turned on.

First, at steps S401 to S403, the adapter controller 51 of the mountadapter 5 a is used to perform processing for sending the opening sidelimit value which is stored in the memory 52 to the camera body 2.

Specifically, first, at step S401, the adapter controller 51 is used toidentify the type of the lens barrel 3 and to judge if the type of thelens barrel 3 was able to be identified or not. The method foridentifying the type of the lens barrel 3 is not particularly limited,but, for example, the memory 52 of the lens adapter 5 a storesidentification information for identifying the type of the lens barrel3, and the adapter controller 51 is used to receive from the lenscontroller 37 lens information including identification information foridentifying the type of the lens barrel 3. Further, the adaptercontroller 51 can compare the identification information of the lensbarrel 3 which was received from the lens controller 37 and theidentification information of the lens barrel 3 which was stored in thememory 52 of the lens adapter 5 a so as to identify the type of the lensbarrel 3. When it was possible to identify the type of the lens barrel3, the routine proceeds to step S402, while when it was not possible toidentify the type of the lens barrel 3, the routine proceeds to stepS403.

At step S402, the type of the lens barrel 3 is identified, so theadapter controller 51 is used to acquire the opening side limit valuewhich corresponds to the type of the lens barrel 3 from the memory 52 ofthe lens adapter 5 a and to send the acquired opening side limit valueto the camera controller 21.

On the other hand, when it was judged at step S401 that it was notpossible to identify the type of the lens barrel 3, the routine proceedsto step S403. At step S403, since the type of the lens barrel 3 couldnot be identified, the adapter controller 51 is used to acquire thepreset predetermined opening side limit value from the memory 52 of thelens adapter 5 a and to send it to the camera controller 21.

At step S404, the camera controller 21 is used for processing to set theaperture value of the optical system (F-value) to the aperture value forfocus detection. Specifically, the camera controller 21 first receivesfrom the adapter controller 51 as the opening side limit value the limitvalue of the opening side of the aperture value of the optical system atthe time of detection of the focus state of the optical system andacquires from the memory 29 as the closing side limit value the limitvalue of the closing side of the aperture value of the optical system atthe time of detection of the focus state of the optical system. Notethat, in the present embodiment, the opening side limit value is storedas the number of closing steps from the open aperture value in thememory 52 of the lens adapter 5 a, so the camera controller 21 uses theopen aperture value and the number of closing steps from the openaperture value as the basis to find the limit value of the opening side(F-value) of the aperture value of the optical system at the time offocus detection as the opening side limit value.

Further, the camera controller 21 uses the acquired opening side limitvalue and closing side limit value as the basis to set the aperturevalue of the optical system for focus detection. Specifically, thecamera controller 21 sets the aperture value of the optical system atthe closing side limit value when the capture aperture value which wasset for capturing the image is a value at the closing side from theclosing side limit value. For example, in the example which is shown inFIG. 10, the case is shown where in a lens barrel 3 in which the openaperture value is F1.2 and the maximum aperture value (maximum F-value)is F16, the opening side limit value is acquired as F2.8 and the closingside limit value is acquired as F5.6. For example, in FIG. 10A, thecapture aperture value is set to F16, and the capture aperture value F16is a value at the closing side from the closing side limit value F5.6,so the camera controller 21 sets the aperture value of the opticalsystem at the closing side limit value F5.6. Further, at FIG. 10B, thecapture aperture value is F8, so, in the same way as in FIG. 10A, thecamera controller 21 sets the aperture value of the optical system atthe closing side limit value F5.6.

Further, when the capture aperture value which was set for the maincapture of the image is the same value as the closing side limit valueor a value at the opening side from the closing side limit value, thecamera controller 21 sets the aperture value of the optical system atthe capture aperture value. For example, at FIG. 10C, the captureaperture value is the same F5.6 as the closing side limit value, so thecamera controller 21 sets the aperture value of the optical system atthe capture aperture value F5.6. Further, at FIG. 10D, the captureaperture value is set at F4, and the capture aperture value F4 is avalue at the opening side from the closing side limit value F5.6, so thecamera controller 21 sets the aperture value of the optical system atthe capture aperture value F4. Similarly, in FIGS. 10E to 10G as well,in the same way as FIG. 10D, the capture aperture value is a value atthe opening side from the closing side limit value, so the cameracontroller 21 sets the aperture value of the optical system at thecapture aperture value.

At step S405, in the same way as step S104 of the first embodiment, atleast one of the light receiving sensitivity Sv and the exposure time Tvis changed so that suitable exposure is obtained at the captured pictureas a whole. Further, at step S406, the camera controller 21 is used tojudge if suitable exposure has been obtained at the captured picture asa whole by the exposure control of step S405. When just a change of thelight receiving sensitivity Sv and exposure time Tv is not enough forsuitable exposure of the captured picture as a whole, the routineproceeds to step S407, while when a change of at least one of the lightreceiving sensitivity Sv and e exposure time Tv is enough for suitableexposure of the captured picture as a whole, the routine proceeds tostep S409.

At step S407, when it is judged that just a change of the lightreceiving sensitivity Sv and exposure time Tv is not enough forobtaining suitable exposure at the captured picture as a whole, thecamera controller 21 is used to change the aperture Av. Specifically,the camera controller 21 uses the brightness value By of the capturedpicture as a whole as the basis to change the aperture Av so that theaperture value of the optical system becomes in a range between theopening side limit value and the closing side limit value when thecapture aperture value is a value at the closing side from the closingside limit value. For example, in FIG. 10A, the capture aperture valueF16 is a value at the closing side from the closing side limit valueF5.6, so the camera controller 21 changes the aperture Av so that theaperture value of the optical system becomes in the range from theopening side limit value F2.8 to the closing side limit value F5.6 andperforms exposure control so that suitable exposure is obtained at thecaptured picture as a whole. Note that, the same is also true of FIG.10B.

Further, the camera controller 21 uses the brightness value By of thecaptured picture as a whole as the basis to change the aperture Av sothat the aperture value of the optical system becomes one in a rangebetween the opening side limit value and the capture aperture value whenthe capture aperture value is a value the same as the closing side limitvalue or a value at the opening side from the closing side limit value.For example, in FIG. 10C, the capture aperture value F5.6 is a value thesame as the closing side limit value F5.6, so the camera controller 21changes the aperture Av so that the aperture value of the optical systembecomes in the range from the opening side limit value F2.8 to thecapture aperture value F5.6. Further, in FIG. 10D, the capture aperturevalue F4 is a value at the opening side from the closing side limitvalue F5.6, so the camera controller 21 changes the aperture Av so thatthe aperture value of the optical system becomes in a range from theopening side limit value F2.8 to the capture aperture value F4.

Note that, the camera controller 21 leaves the aperture value of theoptical system as the capture aperture value when the capture aperturevalue is the same value as the opening side limit value or a value atthe opening side from the opening side limit value. For example, at FIG.10E, the capture aperture value F2.8 is a value the same as the openingside limit value F2.8, so the camera controller 21 leaves the aperturevalue of the optical system as the capture aperture value F2.8. Notethat, the same is true in FIGS. 10F to 10G as well. Further, in thepresent embodiment, for example, as shown in FIGS. 10A to 10D, when itis possible to change the aperture Av within the range of apredetermined aperture value, the camera controller 21, for example, asshown in FIGS. 10A to 10D, changes the aperture Av to the opening sidewith some margin so that it is not necessary to again change theaperture Av even when the brightness value By of the captured picture asa whole again changes.

Note that, the processing of steps S408 to S421 is similar to theprocessing of steps step S107 to S120 of the first embodiment, so theexplanation will be omitted.

As explained above, in the fourth embodiment, the limit value of theopening side of the aperture value of the optical system at the time offocus detection is stored as the opening side limit value in the memory52 of the lens adapter 5 a. The adapter controller 51 uses the lensinformation which was received from the lens barrel 3 as the basis toconfirm the type of the lens barrel 3 and sends the opening side limitvalue corresponding to the lens barrel 3 to the camera controller 21.Due to this, the camera controller 21 uses the opening side limit valuewhich was received from the adapter controller 51 and the closing sidelimit value which was acquired from the memory 29 as the basis to setthe aperture value of the optical system at the time of focus detection.Specifically, in the fourth embodiment, for example, as shown in FIGS.10A to 10D, when the aperture value at the time of capture of an imageis at the closing side from the opening side limit value, by limitingthe aperture value of the optical system at the time of focus detectionto the closing side from the opening side limit value, it is possible tomake the amount of movement of the image plane of the optical systemaccompanying a change of the aperture value of the optical system apredetermined amount or less even when changing the aperture value ofthe optical system from the aperture value at the time of focusdetection to the capture aperture value for capturing an image and as aresult it is possible to make the focal position which was detected atfocus detection within the range of the depth of field of the opticalsystem at the time of capture of an image, so it is possible to capturean image focused on the object.

Further, in the fourth embodiment, as shown in FIGS. 10A to 10B, whenthe aperture value at the time of capture of an image is a value at theclosing side from the closing side limit value, it is possible to limitthe aperture value of the optical system at the time of focus detectionto a value at the opening side from the closing side limit value so asto effectively prevent the occurrence of vignetting at the time of focusdetection and it is possible to suitably detect the focus state of theoptical system. Furthermore, in the present embodiment, as shown inFIGS. 10A to 10G, by limiting the aperture value of the optical systemat the time of focus detection so as not to become a value at theclosing side from the capture aperture value, when capturing an image,the depth of field at the time of capture of the image ends up becomingshallower than the depth of field at the time of focus detection. At thetime of capture of the image, it is possible to effectively prevent anobject focused at the time of focus detection from ending up deviatingfrom the depth of field of the optical system. As a result, it ispossible to capture an image focused on an object well.

Fifth Embodiment

Next, a fifth embodiment of the present invention will be explained withreference to the drawings. In the fifth embodiment, the camera 1 b whichis shown in FIG. 1 operates in the same way as the camera 1 according tothe first embodiment other than operating as shown in FIG. 19. FIG. 19is a flow chart which shows the operation of the camera 1 according tothe fifth embodiment. Note that, the operation of the camera 1 which isshown in FIG. 19 is stated by the power of the camera 1 being turned on.

In the fifth embodiment as well, as shown in FIG. 19, first, at stepS501, the camera controller 21 is used to acquire the opening side limitvalue. Specifically, the camera controller 21 acquires as the openingside limit value from the lens controller 37 the limit value of theopening side of the aperture value of the optical system at the time ofdetection of the focus state of the optical system. Note that, theopening side limit value is stored in the memory 39 as the number ofclosing steps from the open aperture value, so the camera controller 21uses the open aperture value and the number of closing steps from theopen aperture value as the basis to find the limit value of the openingside of the aperture value of the optical system (F-value) at the timeof focus detection as the opening side limit value.

At step S502, the camera controller 21 is used to judge if the shutterrelease button which was provided at the operating unit 28 is halfpressed (first switch SW1 on). When the shutter release button is halfpressed, the routine proceeds to step S503. On the other hand, when theshutter release button is not half pressed, the routine stands by atstep S502.

At step S503, the camera controller 21 is used to judge if the openingside limit value could be acquired at step S501. When it is judged thatthe opening side limit value could be acquired, the routine proceeds tostep S504, while when it is judged that the opening side limit valuecould not be acquired, the routine proceeds to step S505. Here, the lensbarrel 3 according to the present embodiment stores the opening sidelimit value in the memory 39, while the camera controller 21 acquiresthe opening side limit value through the lens controller 37, so theroutine proceeds to step S504. On the other hand, depending on the typeof the lens barrel, sometimes the lens barrel does not store the openingside limit value. When using such a lens barrel, the camera controller21 cannot acquire the opening side limit value from the lens barrel. Inthis case, it is judged that the opening side limit value cannot beacquired and the routine proceeds to step S505.

At step S504, the opening side limit value is acquired, so the cameracontroller 21 is used to set the aperture value of the optical system(F-value) at the opening side limit value. Here, FIG. 20 is a view whichshows one example of the relationship between the aperture value whichis set for focus detection at the fifth embodiment and the captureaperture value. Note that, in the example which is shown in FIG. 20, thesituation is shown where in a lens barrel 3 with an open aperture valueof F1.2 and a maximum aperture value (maximum F-value) of F16, theopening side limit value is acquired as F2.8. At step S504, the openingside limit value is acquired, so as shown in FIG. 20A, the aperturevalue of the optical system is set to the opening side limit value F2.8.

On the other hand, when it was judged at step S503 that the opening sidelimit value could not be acquired, the routine proceeds to step S505.The camera controller 21 is used to set the aperture value of theoptical system (F-value) at the open aperture value. For example, atstep S505, as shown in FIG. 20B, the aperture value of the opticalsystem is set at the open aperture value F1.2.

At steps S506 to S508, in the same way as steps S115, S116, and S111 ofthe first embodiment, exposure control for focus detection is performed,processing for calculation of the amount of defocus is performed, andthe calculated amount of defocus is used as the basis to start the driveoperation of the focus lens 32.

Further, if the drive operation of the focus lens 32 is started, theroutine proceeds to step S509. At step S509, the camera controller 21 isused to set the aperture value of the optical system at the captureaperture value. For example, at FIG. 20A, at step S504, the aperturevalue of the optical system is set at the opening side aperture valueF2.8, but at step S509, the aperture value of the optical system is setat the capture aperture value F4. Further, at FIG. 20B, at step S505,the aperture value of the optical system is set at the open aperturevalue F1.2, but at step S509, the aperture value of the optical systemis set at the capture aperture value F4.

At step S510, in the same way as in step S506, the camera controller 21is used for exposure control for focus detection. Specifically, thecamera controller 21 calculates the brightness value SpotBv in apredetermined region which includes the focus detection area, uses thecalculated brightness value SpotBv and the capture aperture value whichcorresponds to the aperture Av which was set at step S509 as the basisto determine the light receiving sensitivity Sv and the exposure timeTv, and uses the determined light receiving sensitivity Sv and exposuretime Tv as the basis to set the shutter speed of the shutter 23, thecapture sensitivity of the image pickup device 22, etc. Note that, atstep S510 as well, in the same way as step S506, by leaving the apertureAv corresponding to the capture aperture value which was set at stepS509 as is and changing the light receiving sensitivity Sv and exposuretime Tv, exposure control is performed for the image pickup device 22.

Further, at step S511, the amount of defocus is calculated in the statewhere the aperture value of the optical system is set at the captureaperture value. At the following step S512, the amount of defocus whichwas calculated at step S511 is used as the basis to drive the focus lens32.

At step S513, the camera controller 21 is used to judge focusing.Specifically, the camera controller 21 judges whether the absolute valueof the calculated amount of defocus is a predetermined value or less.When the absolute value of the calculated amount of defocus is apredetermined value or less, it is judged that the focus state of theoptical system is a focused state and the routine proceeds to step S514,while when the absolute value of the calculated amount of defocus islarger than the predetermined value, it is judged that the image is notfocused and the routine proceeds to step S511 where the calculation ofthe amount of defocus and the drive of the focus lens 32 based on thecalculated amount of defocus are repeated.

When it is judged that the image has been focused at step S513, theroutine proceeds to step S514 where the camera controller 21 is used tojudge if the shutter release button has been fully pressed (secondswitch SW2 is on). When the second switch SW2 is on, the routineproceeds to step S515, while when the second switch SW2 is not on, theroutine returns to step S502.

At step S515, the image pickup device 22 is used to capture an image,and the captured image data is stored at the memory 24. Note that, inthe present embodiment, at step S509, the aperture value of the opticalsystem is set at the capture aperture value, so the image is capturedwith that capture aperture value.

In this way, in the fifth embodiment, when it is not possible to acquirean opening side limit value from the lens barrel 3, the aperture valueof the optical system is set at the open aperture value to perform focusdetection and the results of this focus detection by the open aperturevalue are used as the basis to start the drive operation of the focuslens 32 and change the aperture value of the optical system from theopen aperture value to the capture aperture value for focus detectionduring the drive operation of the focus lens 32. In this way, in thepresent embodiment, first, the aperture value of the optical system isset at the open aperture value for focus detection, it is possible tosuitably detect the focus state of the optical system whereby even whenthe brightness of the object is low. If setting the aperture value ofthe optical system at the capture aperture value for focus detectionduring the drive operation of the focus lens 32, it is possible toeffectively prevent a change in the image plane accompanying a change ofthe aperture value from causing an object which was focused at the focusdetection to end up losing focus at the time of capture and possible tosuitably capture an image focused on an object.

Further, in the fifth embodiment, when it is possible to obtain anopening side limit value from the lens barrel 3, the aperture value ofthe optical system is set not at the open aperture value, but at theopening side limit value for focus detection. Due to this, in the fifthembodiment, it is possible to make the amount of movement of the imageplane of the optical system in the case of changing the aperture valueof the optical system from the opening side limit value to the captureaperture value a predetermined amount or less and possible to make thefocus position which was detected by the opening side limit value withina range of the depth of field at the time of capture. For this reason,in the present embodiment, even if it is not possible to detect thefocal position by the capture aperture value, it is possible to capturean image focused on the object.

Sixth Embodiment

Next, a sixth embodiment of the present invention will be explainedbased on the drawings. In the sixth embodiment, in the camera 1 which isshown in FIG. 1, the same operation as the camera 1 according to thefirst embodiment is performed other than the operations such as shown inFIG. 21. FIG. 21 is a flow chart which shows the operation of the camera1 according to the sixth embodiment. Note that, the operation of thecamera 1 which is shown in FIG. 21 is started by the power of the camera1 being turned on.

In the sixth embodiment, as shown in FIG. 21, first, at step S601, inthe same way as step S101 of the first embodiment, it is judged if amoving image is being captured. When it is judged that a moving image isbeing captured, the routine proceeds to step S621, while when it isjudged that a moving image is not being captured, the routine proceedsto step S602.

At step S602, the camera controller 21 is used to perform processing forsetting the aperture value of the optical system (F-value) at theaperture value for focus detection. Specifically, the camera controller21 sets the aperture value of the optical system at an aperture valuesuitable for focus detection when the capture aperture value which wasset for capturing an image is larger (closer) than the aperture valuesuitable for focus detection enabling a good precision of focusdetection to be obtained. For example, when the aperture value which issuited for focus detection is F5.6 and the capture aperture value isF16, the camera controller 21 sets the aperture value of the opticalsystem at the aperture value F5.6 which is suited for focus detection.Further, when the capture aperture value is less than the aperture valuewhich is suited for focus detection, the camera controller 21 sets theaperture value of the optical system at the capture aperture value. Forexample, when the aperture value which is suited for focus detection isF5.6 and the capture aperture value is F4.0, the camera controller 21sets the aperture value of the optical system at the capture aperturevalue F4.0. The set aperture value is sent from the camera controller 21to the lens controller 37, while the size of the aperture 34 is adjustedin accordance with the set aperture value. Note that, when aphotographer selects an aperture priority mode, manual exposure mode, orother exposure setting mode, the camera controller 21 sets the captureaperture value which was set by the photographer as it is as theaperture value of the optical system.

At step S603, in the same way as step S103 of the first embodiment, athrough-the-lens image is generated and the through-the-lens image isdisplayed. Further, at steps S604 and S605, in the same way as stepsS104, S105 of the first embodiment, at least one of the light receivingsensitivity Sv and exposure time Tv in the exposure control values ischanged so as to obtain suitable exposure at the captured picture as awhole and it is judged if suitable exposure is obtained at the capturedpicture as a whole. When just a change of the light receivingsensitivity Sv and the exposure time Tv is not enough for suitableexposure of the captured picture as a whole, the routine proceeds tostep S606, while when change of at least one of the light receivingsensitivity Sv and exposure time Tv gives suitable exposure at thecaptured picture as a whole, the routine proceeds to step S608.

At step S606, it is judged that suitable exposure cannot be obtained atthe captured picture as a whole by just changing the light receivingsensitivity Sv and exposure time Tv, so the camera controller 21 is usedto change the aperture Av. Specifically, the camera controller 21 usesthe brightness value By of the captured picture as a whole as the basisto calculate the aperture Av and changes the aperture value of theoptical system to a value corresponding to the calculated aperture Av.Further, in the present embodiment, the camera controller 21 changes theaperture Av so that the aperture value of the optical system becomeswithin the range of the capture aperture value or less. Further, thecamera controller 21 changes the aperture Av in the direction where theaperture value of the optical system becomes smaller (direction whereaperture size becomes larger) with some margin so that it is notnecessary to again change the aperture Av even when the brightness valueBy of the captured picture as a whole again changes.

The processing of steps S607 to S620 are similar to the processing ofsteps S107 to S120 of the first embodiment, so the explanation will beomitted.

Note that, when it is judged at step S601 that a moving image is beingcaptured, the routine proceeds to step S621. At step S621, the cameracontroller 21 is used for exposure control so as to obtain exposuresuitable for capturing a moving image. Specifically, the cameracontroller 21 measures the light by multi-pattern photometry since itgives priority to the appearance of the moving image, calculates thebrightness value By of the captured picture as a whole, and uses thecalculated brightness value By as the basis to determine the lightreceiving sensitivity Sv and exposure time Tv so as to obtain suitableexposure at the captured picture as a whole. In particular, duringcapture of a moving image, the aperture Av is left fixed and only thelight receiving sensitivity Sv and exposure time Tv are changed forexposure control.

Further, at step S622, the camera controller 21 is used to detect thefocus state of the optical system and the focus is adjusted by the focuslens 32 in accordance with the detected focus state. Specifically, thecamera controller 21 uses the captured image data as the basis tocalculate the amount of defocus and judge if the amount of defocus couldbe calculated in the same way as steps S611 and S615 to S619. Further,when the amount of defocus is calculated, the calculated amount ofdefocus is used as the basis to drive the focus lens 32, while when theamount of defocus could not be calculated, scan operation processing isperformed. Further, the routine proceeds to step S623 where the imagepickup device 22 is used to capture a moving image, and the image dataof the moving image which is captured by the camera controller 21 isstored in the memory 24.

In the above way, in the sixth embodiment, when the capture aperturevalue for capturing an image is larger than a predetermined aperturevalue suitable for focus detection, the aperture 34 is controlled sothat the aperture value of the optical system becomes an aperture valuesuitable for focus detection and the focus state of the optical systemis detected by the aperture value suitable for focus detection. Due tothis, in the sixth embodiment, the following effects can be exhibited.That is, in the past, the aperture value at the time of capture of animage sometimes became smaller than the aperture value at the time offocus detection. In such a case, sometimes the depth of field whencapturing an image became shallower than the depth of field at the timeof focus detection, the object which was focused at the time of focusdetection ends up deviating from the depth of field of the opticalsystem at the time of capturing the image, and it was not possible tocapture an image focused at the object. As opposed to this, in thepresent embodiment, since the aperture value of the optical systembecomes an aperture value suitable for focus detection, the aperturevalue at the time of capture of an image becomes larger than theaperture value at the time of focus detection, so the depth of field atthe time of capture of the image becomes deeper than the depth of fieldat the time of focus detection. As a result, the object which wasfocused at the time of focus detection becomes within the depth of fieldof the optical system even at the time of capturing an image, so it ispossible to capture an image focused at the object.

Further, in the sixth embodiment, the light receiving sensitivity Sv andexposure time Tv in the exposure control values are changed withpriority for exposure control. Further, when the desired exposure cannotbe obtained with just a change of the light receiving sensitivity Sv andexposure time Tv, the aperture Av is changed for exposure control. Dueto this, in the sixth embodiment, it is possible to effectively preventthe aperture value of the optical system from being changedcorresponding to a change of the aperture Av, so the following effectscan be exhibited. That is, change of the aperture value of the opticalsystem accompanies mechanical operation of the aperture 34, so at thetime of focus detection, by changing the light receiving sensitivity Svand exposure time Tv with priority, it is possible to shorten the timewhich is required for focus detection. Further, to obtain a brightnesssuitable for focus detection at the time of focus detection by the phasedifference detection system, sometimes a plurality of image dataobtained for each predetermined time period are added and the addedimage data is used as the basis to calculate the amount of defocus.Here, the conversion coefficient for converting the amount of deviationof the image based on the image data to the amount of defocus is a valuecorresponding to the aperture value of the optical system, so if theaperture value of the optical system ends up changing at the time offocus detection, sometimes the added image data cannot be used as thebasis to suitably calculate the amount of defocus. Even in such a case,according to the present embodiment, it is possible to change the lightreceiving sensitivity Sv and exposure time Tv with priority to suitablycalculate the amount of defocus, so it is possible to improve theprecision of focus detection. Furthermore, when displaying athrough-the-lens image or when capturing a moving image, if the aperturevalue of the optical system is changed, for example, sometimes the depthof field ends up changing, the object ends up becoming blurred, and theappearance of the image otherwise ends up falling. In such a case, it ispossible to change the light receiving sensitivity Sv and exposure timeTv with priority to improve the appearance of the through-the-lens imageand moving image. In particular, when capturing a moving image, theaperture value of the optical system is set as the capture aperturevalue, so it is possible to capture a moving image well. Further, in thesixth embodiment, even if the brightness of the object changes, it ispossible to change the aperture Av in the exposure control values with amargin so that it is not necessary to again change the aperture value ofthe optical system and thereby lower the frequency of change of theaperture value of the optical system and possible to improve theappearance of the through-the-lens image or moving image.

Seventh Embodiment

Next, the seventh embodiment of the present invention will be explainedbased on the drawings. In the seventh embodiment, in the camera 1 whichis shown in FIG. 1, a similar operation as with the camera 1 accordingto the first embodiment is performed except for the operation such asshown in FIG. 22 and FIG. 23. FIG. 22 and FIG. 23 are flow charts whichshow the operation of the camera 1 according to the seventh embodiment.Note that, the operation of the camera 1 which is shown in FIG. 22 andFIG. 23 is started by the power of the camera 1 being turned on.

In the seventh embodiment, as shown in FIG. 22, first, at step S701, inthe same way as step S101 of the first embodiment, it is judged if amoving image is being captured. When it is judged that a moving image isbeing captured, the routine proceeds to step S725 which is shown in FIG.23, while when it is judged that a moving image is not being captured,the routine proceeds to step S702.

At step S702, the camera controller 21 is used to detect the brightnessof the object based on the output of the image pickup device 22 andjudge if emission of illumination light for focus detection is requiredby the detected brightness of the object. For example, when thebrightness of the object is less than a predetermined brightness valuefor suitable focus detection, the camera controller 21 can judge thatthe brightness of the object is not sufficient for detection of thefocus state of the optical system and the light 210 has to emitillumination light for focus detection. When it is judged that emissionof illumination light for focus detection is necessary, the routineproceeds to step S710, while when it is judged that emission ofillumination light for focus detection is not necessary, the routineproceeds to step S703.

At step S703, in the same way as step S102 of the first embodiment, theopening side limit value is acquired from the lens barrel 3, the closingside limit value is acquired from the memory 29, and the acquiredopening side limit value and closing side limit value are used as thebasis to set the aperture value of the optical system for focusdetection. Further, at steps S704 and S705, in the same way as stepsS103 and S104 of the first embodiment, the through-the-lens image isdisplayed, then the light receiving sensitivity Sv and the exposure timeTv are determined so that suitable exposure is obtained at the capturedpicture as a whole.

Further, at step S706, the camera controller 21 is used to judge if thecapture aperture value is the same value as the opening side limit valueor a value at the opening side from the opening side limit value. Whenthe capture aperture value is the same value as the opening side limitvalue or a value at the opening side from the opening side limit value,the routine proceeds to the later explained step S708, while when thecapture aperture value is not the same value as the opening side limitvalue or a value at the opening side from the opening side limit value,the routine proceeds to step S707. For example, in the example which isshown in FIGS. 10A to 10D, the capture aperture value is a value at theclosing side from the opening side limit value, so the routine proceedsto step S707. On the other hand, in the example which is shown in FIGS.10E to 10G, the capture aperture value is the same value as the openingside limit value or a value at the closing side from the opening sidelimit value, so the routine proceeds to step S708.

At step S707, the camera controller 21 is used to judge if suitableexposure is obtained at the captured picture as a whole based on theaperture Av which corresponds to the aperture value which was set atstep S703 and the light receiving sensitivity Sv and the exposure timeTv which were determined at step S705. When it is judged that suitableexposure is obtained at the captured picture as a whole, the routineproceeds to step S708. At step S708, the camera controller 21 uses theaperture Av corresponding to the aperture value which was set at stepS703 and the light receiving sensitivity Sv and exposure time Tv whichare determined at step S705 as the basis for exposure control for theimage pickup device 22.

On the other hand, when it is judged at step S707 that suitable exposureis not obtained at the captured picture as a whole, the routine proceedsto step S709. At step S709, the camera controller 21 is used to set theaperture value of the optical system at the opening side limit value sothat suitable exposure is obtained at the captured picture as a whole.Further, at the following step S708, the camera controller 21 uses theaperture Av corresponding to the aperture value of the optical system(opening side limit value) which was set at step S709 as the basis todetermine the light receiving sensitivity Sv and exposure time Tv givingsuitable exposure at the captured picture as a whole and uses thedetermined light receiving sensitivity Sv and exposure time Tv and theaperture Av corresponding to the aperture value of the optical system(opening side limit value) which was set at step S709 as the basis forcontrol of exposure of the image pickup device 22. For example, in theexample which is shown in FIG. 10A, at step S703, the closing side limitvalue F5.6 is set as the aperture value of the optical system for focusdetection, but when suitable exposure of the captured picture as a wholecannot be obtained with an aperture value of the optical system of F5.6,at this step S709, the aperture value of the optical system is set atthe opening side limit value F2.8. Note that, in the present embodiment,at step S709, the aperture value of the optical system is set to theopening side limit value, but the invention is not limited to this. Forexample, the aperture value of the optical system may be set to anaperture value of a value in the range between the closing side limitvalue and the opening side limit value by which suitable exposure can beobtained at the captured picture as a whole.

Further, when, at step S706, it is judged that the capture aperturevalue is the same value as the opening side limit value or a value atthe opening side from the opening side limit value, the routine proceedsto step S708. Here, as explained above, when it is judged that thecapture aperture value is the same value as the opening side limit valueor a value at the opening side from the opening side limit value, asshown in the example which is shown in FIGS. 10E to 10G, at step S703,the aperture value of the optical system for focus detection is set atthe capture aperture value. For this reason, in this case, at step S708,the camera controller 21 uses the brightness value By of the capturedpicture as a whole and the aperture value of the optical system which isset at step S703, that is, the aperture Av which corresponds to thecapture aperture value, as the basis to determine the light receivingsensitivity Sv and the exposure time Tv by which suitable exposure isobtained at the captured picture as a whole and uses the determinedlight receiving sensitivity Sv and exposure time Tv and the aperture Avwhich corresponds to the aperture value of the optical system (captureaperture value) as the basis to control exposure for the image pickupdevice 22.

Furthermore, when it was judged at step S702 that illumination for focusdetection was necessary, the routine proceeds to step S710. At stepS710, the camera controller 21 is used to set the aperture value of theoptical system at the opening side limit value. Further, at thefollowing step S711, in the same way as step S704, the through-the-lensimage starts to be displayed, then the routine proceeds to step S708where the light 210 is used for emission of illumination light for focusdetection, the brightness value By which was obtained by emission of theillumination light and the aperture Av corresponding to the aperturevalue of the optical system (opening side limit value) which was set atstep S710 are used as the basis to determine the light receivingsensitivity Sv and exposure time Tv, and the determined light receivingsensitivity Sv and exposure time Tv and the aperture Av corresponding tothe aperture value of the optical system (opening side limit value) areused as the basis for control of exposure of the image pickup device 22.

The processing of the following steps S712 to S724 is similar to theprocessing of steps S108 to S120 of the first embodiment, so itsexplanations will be omitted.

Further, when it is judged at step S701 which is shown in FIG. 22 that amoving image is being captured, the routine proceeds to step S725 whichis shown in FIG. 23. At step S725, the camera controller 21 is used togive priority to the appearance of the moving image and set the aperturevalue of the optical system at the capture aperture value, and, at thefollowing step S726, the image data of the moving image which iscaptured by the image pickup device 22 is displayed through the cameracontroller 21 on the electronic viewfinder 26. Further, at step S727,the camera controller 21 is used to measure the light by multi-patternphotometry, and the calculated brightness value By of the capturedpicture as a whole and aperture Av corresponding to the aperture value(capture aperture value) which was set at step S725 are used as thebasis to determine the light receiving sensitivity Sv and exposure timeTv so as to obtain suitable exposure at the captured picture as a whole.

At step S728, the camera controller 21 uses the light receivingsensitivity Sv and exposure time Tv which were determined at step S727and the aperture Av corresponding to the aperture value (captureaperture value) which was set at step S725 as the basis for control ofexposure for the image pickup device 22. Further, at step S729, thecamera controller 21 is used for detection of the focus state of theoptical system and for adjustment of the focus of the focus lens 32corresponding to the detected focus state. Specifically, the cameracontroller 21 uses the image data which was obtained by the exposurewhich was set at step S728 as the basis to calculate the amount ofdefocus and judge if amount of defocus could be calculated. When theamount of defocus is calculated, the calculated amount of defocus isused as the basis to drive the focus lens 32, while when the amount ofdefocus is not calculated, scan operation processing is performed in thesame way as step S722. Further, the routine proceeds to step S730 wherethe image pickup device 22 and the camera controller 21 are used tocapture a moving image.

Next, the operation of the camera 1 of the seventh embodiment will beexplained based on FIG. 10. For example, in the example which is shownin FIG. 10A, the capture aperture value F16 is a value at the closingside from the closing side limit value F5.6, so first the aperture valueof the optical system is set at the closing side limit value F5.6 (stepS703). Further, when it is judged that suitable exposure can be obtainedin the state setting the aperture value of the optical system at theclosing side limit value F5.6 (step S707=Yes), exposure control forfocus detection is performed by a closing side limit value F5.6 beforethe shutter release button is half pressed (step S708), while when it isjudged that suitable exposure cannot be obtained in the state settingthe aperture value of the optical system at the closing side limit valueF5.6 (step S707=No), the aperture value of the optical system is changedto the opening side limit value F2.8 (step S709) and exposure controlfor focus detection is performed by an opening side limit value F2.8before the shutter release button is half pressed (step S708). Further,after the shutter release button is half pressed, the focus lens 32 isdriven based on the amount of defocus which was calculated before theshutter release button was half pressed without performing exposurecontrol for focus detection (step S715). Note that, when the reliabilityof the amount of defocus is low and the amount of defocus cannot becalculated (step S714=No), the aperture value of the optical system ischanged in the range between the closing side limit value and openingside limit value, and the changed aperture value is used as the basisfor exposure control for focus detection (step S719). After the focus isadjusted by the focus lens 32, the aperture value of the optical systemis changed to the capture aperture value F16 (step S717) and a stillimage is captured by the capture aperture value F16 (step S718). Notethat, the same thing is done in the example which is shown in FIG. 10Bas well.

Further, in the example which is shown in FIG. 10D, the capture aperturevalue F4 is a value at the opening side from the closing side limitvalue F5.6, so, first, the aperture value of the optical system is setto the capture aperture value F4 (step S703). Further, when it is judgedthat suitable exposure is obtained in the state setting the aperturevalue of the optical system at the capture aperture value F4 (stepS707=Yes), exposure control for focus detection is performed by thecapture aperture value F4 before the shutter release button is halfpressed (step S708). On the other hand, when it is judged that suitableexposure is not obtained in the state setting the aperture value of theoptical system at the capture aperture value F4 (step S707=No), theaperture value of the optical system is changed to the opening sidelimit value F2.8 (step S709) and exposure control for focus detection isperformed by the opening side limit value F2.8 before the shutterrelease button is half pressed (step S708). Further, after the shutterrelease button is half pressed, the focus lens 32 is driven based on theamount of defocus which was calculated before the shutter release buttonwas half pressed without performing exposure control for focus detection(step S715). Note that, when the reliability of the amount of defocus islow and the amount of defocus cannot be calculated (step S714=No), theaperture value of the optical system is changed within the range of thecapture aperture value and the opening side limit value, and the changedaperture value is used as the basis for exposure control for focusdetection (step S719). Further, after the focus is adjusted by the focuslens 32, the aperture value of the optical system is changed to thecapture aperture value F4 (step S717) and a still image is captured bythe capture aperture value F4 (step S718). Note that, in the examplewhich is shown in FIGS. 10C and 10E as well, the same thing is done asin the example which is shown in FIG. 10D.

Furthermore, in the example which is shown in FIG. 10F, the captureaperture value F2 is a value at the opening side from the opening sidelimit value F2.8, so, first, the aperture value of the optical system isset to the capture aperture value F2 (step S703). Further, in theexample which is shown in FIG. 10F, at step S706, it is judged that thecapture aperture value is a value at the opening side from the openingside limit value (step S706=Yes) and, before the shutter release buttonis half pressed, exposure control for focus detection is performed bythe capture aperture value F2 (step S708). Further, after the shutterrelease button is half pressed, exposure control for focus detection isnot performed. The focus lens 32 is driven based on the amount ofdefocus which is calculated before the shutter release button is halfpressed (step S715). After adjusting the focus by the focus lens 32, theaperture value of the optical system is left as the capture aperturevalue F2 (step S717) and a still image is captured by the captureaperture value F2 (step S718). Note that, in the example which is shownin FIGS. 10E and 10G as well, a similar routine is performed as in theexample which is shown in FIG. 10F.

As explained above, in the seventh embodiment, before the shutterrelease button is half pressed, the opening side limit value and theclosing side limit value are used as the basis to set the aperture valueof the optical system to an aperture value suitable for focus detection,and the set aperture value of the optical system is used for exposurecontrol for focus detection. Due to this, in the seventh embodiment, inthe interval after the shutter release button is half pressed to whenthe focus lens 32 starts to be driven, the time which is required forexposure control for focus detection (for example, including the timefor driving the aperture 34 in accordance with the aperture valuesuitable for focus detection and the time after completion of the driveof the aperture 34 to stabilization of exposure) can be eliminated. Thetime from when the shutter release button is half pressed to when thefocus lens 32 is driven can be shortened.

For example, when the capture aperture value is a value at the closingside from the closing side limit value, as the mentioned aperture valuesuitable for focus detection, camera controller 21 can set a aperturevalue of the optical system at a value near the closing limit valuewithin the range between the closing side limit value and the openingside limit value as the mentioned aperture value suitable for focusdetection. In this case, since the value at near closing limit value isnear the capture aperture value, it is possible to give preciseauto-focus control in a situation similar to the time of capturing aimage.

Further, as the mentioned aperture value suitable for focus detection,camera controller 21 can set a aperture value of the optical system at avalue near the opening limit value within the range between the closingside limit value and the opening side limit value. In this case, it ispossible to give precise auto-focus control in a bright situation.

Further, as the mentioned aperture value suitable for focus detection,camera controller 21 can set a aperture value of the optical system at apredetermined value within the range between the closing side limitvalue and the opening side limit value the predetermined value can bestored in memory 29 or memory 39. In this case, when the predeterminedvalue stored in the memory 29,39 is a value suitable for generalcapturing images, it is possible to give precise auto-focus controlsuitable for general capturing images.

Furthermore, camera controller 21 can change aperture value for focusdetection corresponding to the state of the capturing a image such asthe result of scene recognition, the capture mode (scenery capture mode,sport capture mode, portrait capture mode, etc.), and the brightness ofobject. So that, it is possible to give precise auto-focus controlsuitable for the state of the capturing image.

Further, in the seventh embodiment, when the reliability of the amountof defocus is low even after the shutter release button is half pressed,the aperture value of the optical system can be changed within the rangebetween the closing side limit value and the opening side limit valuesuitable for focus detection so as to suitably calculate the amount ofdefocus and as a result the focus detection by the phase differencedetection system can be suitably performed. Furthermore, in the seventhembodiment, when it is necessary to emit illumination light for focusdetection, it is possible to set the aperture value of the opticalsystem at the opening side limit value so as to set the aperture valueof the optical system to an aperture value which is better suited tofocus detection. In addition, in the present embodiment, when capturinga moving image, it is possible to fix the aperture value of the opticalsystem at the capture aperture value so as to capture a moving imagewith a good appearance.

Note that, the embodiments which were explained above were described forfacilitating understanding of the present invention and were notdescribed for limiting the present invention. Therefore, the elementswhich were disclosed in the above embodiments include all design changesand equivalents which fall under the technical scope of the presentinvention.

For example, in the above-mentioned embodiments, the shutter releasebutton which was provided at the operating unit 28 was half pressed soas to start the adjustment of focus by the focus lens 32, but theinvention is not limited to this configuration. For example, it is alsopossible to connect a PC to the camera 1 and have the camera 1 receive asignal from the PC so as to start up the adjustment of focus by thefocus lens 32 or to have the camera 1 receive a signal from a remotecontroller corresponding to the camera 1 so as to start up theadjustment of focus by the focus lens 32. In this case, for example, atstep S110 of the first embodiment, it is also possible to judge if asignal for starting up the adjustment of focus by the focus lens 32 hasbeen received from the PC or remote controller.

Further, in the above-mentioned third embodiment, the configuration isillustrated where when changing the aperture value of the optical systemfrom the aperture value at the time of focus detection to the captureaperture value when capturing the image, the variable amount of theaperture value is set so that the amount of movement of the image planeaccompanying a change of the aperture value becomes a predeterminedamount enabling good capture of an image or less, but in addition tothis configuration, it is also possible to limit the aperture value ofthe closing side at the variable amount of the aperture value so as toeffectively prevent occurrence of vignetting.

Furthermore, in the above-mentioned fifth embodiment, the configurationis illustrated where when acquiring the opening side limit value fromthe lens barrel 3, as shown in FIG. 20A, the aperture value of theoptical system is set at the opening side limit value for focusdetection, and the aperture 34 is closed so that the aperture value ofthe optical system becomes the capture aperture value during the driveoperation of the focus lens 32 based on the results of focus detection,but, for example, a configuration is also possible where even whenacquiring the opening side limit value from the lens barrel 3, theaperture value of the optical system is set at the open aperture valuefor focus detection, and the aperture 34 is closed so that the aperturevalue of the optical system becomes the same value as the opening sidelimit value or a value at the closing side from the opening side limitvalue during the drive operation of the focus lens 32 based on theresults of focus detection. For example, as shown in FIG. 20C, even whenthe opening side limit value could be acquired as F2.8, the aperturevalue of the optical system is set to the open aperture value F1.2 forfocus detection. Further, the aperture 34 is closed for focus detectionso that the aperture value of the optical system becomes the same valueas opening side limit value F2.8 or a value at the closing side from theopening side limit value F2.8 during the drive operation of the focuslens 32 based on the results of this focus detection. For example, inFIG. 20C, the aperture value of the optical system is set at a value atthe closing side from the opening side limit value, that is, F3.5, forfocus detection during drive operation of the focus lens 32. Further,when capturing an image, the aperture value of the optical system is setat capture aperture value F4 for capturing an image. Due to this, it ispossible to make the amount of movement of the image plane at the timeof shifting from focus detection to image capture a predetermined amountor less and possible to capture an image focused on the object.

Further, in the above-mentioned fifth embodiment, the configuration wasillustrated where when the opening side limit value could be acquiredfrom the lens barrel 3, the aperture value of the optical system is setat the opening side limit value for focus detection, but a configurationis also possible where, in addition to this configuration, when thefocus state of the optical system could not be detected in the statewhere the aperture value of the optical system is made the opening sidelimit value, the aperture value of the optical system is changed to theopen aperture value for focus detection. Due to this, even when thebrightness of the object is low etc., the focus state of the opticalsystem can be more suitably detected.

In addition, in the above-mentioned fifth embodiment, the configurationis illustrated where the limit value of the opening side of the aperturevalue of the optical system at the time of focus detection is acquiredas the opening side limit value, but in addition to this, for example,the limit value of the closing side of the aperture value of the opticalsystem at the time of focus detection is stored in advance as theclosing side limit value in the memory which is provided at the cameracontroller 21 and this closing side limit value is used as the basis forfocus detection. Note that, the closing side limit value can effectivelyprevent occurrence of vignetting at the time of focus detection, forexample, and can be made the value at the most closing side among theaperture values able to give good precision of focus detection. Forexample, as shown in FIG. 20D, in a situation where the closing sidelimit value is stored as F5.6 and the capture aperture value is set atF8, the capture aperture value F8 is a value at the closing side fromthe closing side limit value, that is, F5.6. In such a case, it ispossible to limit the aperture value of the optical system during thedrive operation of the focus lens 32 to the closing side limit valueF5.6 for focus detection so as to effectively prevent the occurrence ofvignetting at the time of focus detection and possible to suitablydetect the focus state of the optical system. Note that, in this case,after focus detection, the aperture value of the optical system is setat the capture aperture value F8 and the image is captured at the setcapture aperture value.

Further, in the above-mentioned fifth embodiment, the configuration isillustrated where when setting the aperture value of the optical systemat the opening side limit value or open aperture value for focusdetection and using the results of this focus detection as the basis tostart the drive operation of the focus lens 32, the aperture value ofthe optical system is immediately set at the capture aperture value,but, for example, a configuration is also possible where the aperture 34is gradually closed so as to gradually change the aperture value of theoptical system from the opening side limit value or open aperture valueto the capture aperture value during the drive operation of the focuslens 32. Further, when storing the closing side limit value and thecapture aperture value is a value at the closing side from the closingside limit value, a configuration is also possible where the aperture 34is gradually closed so as to gradually change the aperture value of theoptical system from the opening side limit value or open aperture valueto the closing side limit value during the drive operation of the focuslens 32.

In addition, in the above-mentioned fifth embodiment, a configuration ispossible where the camera controller 21 uses the brightness of theobject as the basis to operate the above-mentioned camera 1 only when itis judged necessary to emit illumination light by the light 210.

Further, in the above-mentioned seventh embodiment, the configuration isillustrated where the amount of defocus is calculated before the shutterrelease button which was provided at the operating unit 28 is halfpressed and where when the photographer half presses the shutter releasebutton, the amount of defocus which was calculated before the shutterrelease button is half pressed is used as the basis to drive the focuslens 32, but the invention is not limited to this configuration. Forexample, a configuration is also possible where when, regardless ofwhether the shutter release button is half pressed or not, the capturemode which drive the focus lens 32 based on the calculated amount ofdefocus is selected, the calculated amount of defocus is used as thebasis to drive the focus lens 32 from before the shutter release buttonis half pressed.

Further, in the above-mentioned embodiments, the configuration wasillustrated of storing in advance the opening side limit value in thememory of the lens controller 37, but the invention is not limited tothis configuration. For example, a configuration is also possible where,when the lens controller 37 does not store the opening side limit valueor when the opening side limit value cannot be acquired from the lenscontroller 37, the opening side limit value may be determined by thecamera controller 21.

Furthermore, in the above-mentioned seventh embodiment, it is preferableto configure the system so as to set the aperture value of the opticalsystem at an aperture value suitable for focus detection from before theshutter release button is half pressed even when the focus detectionarea is outside of the region on the picture at which focus detection ispossible by the phase difference detection system when setting theaperture value of the optical system at step S703. Due to this, forexample, when the focus detection area returns to the region on thepicture at which focus detection is possible by the phase differencedetection system from outside the region and right after that theshutter release button is half pressed, it is possible to quickly focuson the object.

In addition, in the above-mentioned seventh embodiment, theconfiguration is illustrated of setting the aperture value of theoptical system to the aperture value for focus detection and performingexposure control for focus detection before the shutter release buttonis half pressed, but, for example, when connecting a PC to the camera 1and having the camera 1 receive a signal from the PC so as to start theadjustment of focus by the focus lens 32 or when having the camera 1receive a signal from a remote controller corresponding to the camera 1so as to start the adjustment of focus by the focus lens 32, it ispossible to set the aperture value of the optical system at the aperturevalue for focus detection and perform exposure control for focusdetection from before receiving a signal for starting focus adjustmentby the focus lens 32 from the PC or remote controller.

Further, in the above-mentioned embodiment, a configuration isillustrated where the light 210 is provided at the camera body 2, butthe invention is not limited to this configuration. For example, aconfiguration is also possible where a strobe device which can beconnected to the camera body 2 is provided and the illumination lightfor focus detection is emitted from the strobe device.

Further, in the above-mentioned embodiment, the electro-magneticaperture which is electrically controlled by camera body 2 is provided.For example, a configuration is also possible where an aperture which ismechanically controlled by camera body 2 using machine paths such as alever component is provided.

Note that, the camera 1 of the above-mentioned embodiment is notparticularly limited. For example, the present invention may be appliedto a digital video camera, single lens reflex digital camera, digitalcamera with a built-in lens, camera for a mobile phone, or other opticaldevice.

REFERENCE NOTATION LIST

1, 1 a, 1 b . . . digital camera

-   2 . . . camera body-   21 . . . camera controller-   22 . . . image pickup device-   221 . . . capture pixel-   222 a, 222 b . . . focus detection pixel-   28 . . . operating unit-   210 . . . light-   3 . . . lens barrel-   32 . . . focus lens-   36 . . . focus lens drive motor-   37 . . . lens controller-   5, 5 a . . . lens adapter-   51 . . . adapter controller-   52 . . . memory

1. An exchangeable lens which can be directly or indirectly detachablyattached to a camera, the lens comprising: an optical system includingan aperture; and a driver which drives the aperture so that an aperturevalue of the aperture for detecting a focal position of the opticalsystem becomes a first aperture value or less when the aperture valuefor capturing an image is larger than the first aperture value, and setsthe aperture value of the aperture for detecting the focal position ofthe optical system becomes the aperture value for capturing the imagewhen the aperture value for capturing the image is the first aperturevalue or less.
 2. The exchangeable lens as set forth in claim 1, whereinthe driver drives the aperture so that the aperture value for detectingthe focal position of the optical system becomes the first aperturevalue when the aperture value for capturing an image is larger than thefirst aperture value.
 3. The exchangeable lens as set forth in claim 1,wherein the driver drives the aperture so that the aperture value of theaperture for detecting the focal position of the optical system becomesa value smaller than the aperture value for capturing the image when thecamera captures a dark object.
 4. The exchangeable lens as set forth inclaim 1, wherein the driver drives the aperture so that the aperturevalue of the aperture for detecting the focal position of the opticalsystem becomes a minimum aperture value when the camera captures a darkobject. 5-12. (canceled)
 13. The exchangeable lens as set forth in claim1, wherein the driver drives the apertures so that the aperture value ofthe aperture for detecting the focal position of the optical systembecomes the aperture value of the aperture for capturing a moving imagewhen the camera captures the moving image.
 14. The exchangeable lens asset forth in claim 13, wherein the driver drives the apertures so thatthe aperture value of the aperture for detecting the focal position ofthe optical system becomes the first aperture value or less when thecamera captures a still image capture and the aperture value of theaperture for capturing the still image capture is larger than the firstaperture value and so that the aperture value of the aperture fordetecting the focal position of the optical system becomes the aperturevalue of the aperture for capturing the still image capture when theaperture value of the aperture for capturing the still image capture isthe first aperture value or less.
 15. The exchangeable lens as set forthin claim 1, further comprising a memory which stores information of thefirst aperture value.
 16. The exchangeable lens as set forth in claim 1,further comprising a transmitter which sends information of a minimumaperture value of the aperture to the camera.
 17. A mount adapter whichcan be detachably attached to a camera and/or an exchangeable lens whichhas an optical system including an aperture, the mount adaptercomprising: a driver which drives the aperture so that an aperture valueof the aperture for detecting a focal position of the optical systembecomes a first aperture value or less when the aperture value forcapturing an image is larger than the first aperture value, and theaperture value of the aperture for detecting the focal position of theoptical system becomes the aperture value for capturing the image whenthe aperture value for capturing the image is the first aperture valueor less.
 18. The mount adapter as set forth in claim 17, wherein thedriver drives the aperture so that the aperture value for detecting thefocal position of the optical system becomes the first aperture valuewhen the aperture value for capturing an image is larger than the firstaperture value.
 19. The mount adapter as set forth in claim 17, thedriver drives the aperture so that the aperture value of the aperturefor detecting the focal position of the optical system becomes a valuesmaller than the aperture value for capturing the image when the cameracaptures a dark object.
 20. The mount adapter as set forth in claim 17,the driver drives the aperture so that the aperture value of theaperture for detecting the focal position of the optical system becomesa minimum aperture value when the camera captures a dark object.
 21. Themount adapter as set forth in claim 17, wherein the driver drives theapertures so that the aperture value of the aperture for detecting thefocal position of the optical system becomes the aperture value of theaperture for capturing a moving image when the camera captures themoving image.
 22. The mount adapter as set forth in claim 21, whereinthe driver drives the apertures so that the aperture value of theaperture for detecting the focal position of the optical system becomesthe first aperture value or less when the camera captures a still imagecapture and the aperture value of the aperture for capturing the stillimage capture is larger than the first aperture value and so that theaperture value of the aperture for detecting the focal position of theoptical system becomes the aperture value of the aperture for capturingthe still image capture when the aperture value of the aperture forcapturing the still image capture is the first aperture value or less.23. The mount adapter as set forth in claim 17, further comprising amemory which stores information of the first aperture value.
 24. Themount adapter as set forth in claim 17, further comprising: a receiverwhich receives information of a minimum aperture value of the aperturefrom a exchangeable lens and; a transmitter which sends the informationof the minimum aperture value of the aperture to the camera.
 25. Acamera comprising: an imaging sensor which captures an image by anoptical system including an aperture and outputs a signal; a detectorwhich detects a focal position where an image by the optical system isfocused in the imaging sensor based on the signal; and a controllerwhich sets an aperture value of the aperture for detecting the focalposition by the detector to a first aperture value or less when theaperture value for capturing an image by the imaging sensor is largerthan the first aperture value, and sets the aperture value of theaperture for detecting the focal position by the detector to theaperture value for capturing the image by the imaging sensor when theaperture value for capturing the image by the imaging sensor is thefirst aperture value or less.
 26. The camera as set forth in claim 25,wherein the controller sets the aperture value for detecting the focalposition by the detector to the first aperture value when the aperturevalue for capturing an image by the imaging sensor is larger than thefirst aperture value.
 27. The camera as set forth in claim 25, whereinthe controller sets the aperture value of the aperture for detecting thefocal position by the detector to a value smaller than the aperturevalue for capturing the image by the imaging sensor when the signaloutput from the imaging sensor is smaller than a predetermined value.28. The camera as set forth in claim 25, wherein the controller sets theaperture value of the aperture for detecting the focal position by thedetector to a minimum aperture value when the signal output from theimaging sensor is smaller than a predetermined value.
 29. The camera asset forth in claim 25, wherein the controller controls the aperturevalue of the aperture for detecting the focal position by the detectoron the basis of the signal output from the imaging sensor when thesignal output from the imaging sensor is smaller than a predeterminedvalue.
 30. The camera as set forth in claim 25, comprising the selectingunit which is configured to be able to select a moving image capture ora still image capture by the imaging sensor, wherein the controllerwhich sets the aperture value of the aperture for detecting the focalposition of the optical system to the aperture value of the aperture forcapturing a moving image by the imaging sensor when the selecting unitselects the moving image capture.
 31. The camera as set forth in claim30, wherein the controller sets the aperture value of the aperture fordetecting the focal position of the optical system to the first aperturevalue or less when the selecting units selects the still image captureand the aperture value of the aperture for capturing the still imagecapture is larger than the first aperture value and sets the aperturevalue of the aperture for detecting the focal position of the opticalsystem to the aperture value of the aperture for capturing the stillimage capture when the aperture value of the aperture for capturing thestill image capture is the first aperture value or less.
 32. The cameraas set forth in claim 25, further comprising a memory which storesinformation of the first aperture value.
 33. The camera as set forth inclaim 25, further comprising: a detaching unit configured to be able todetach an exchangeable lens or a mount adapter to be coupled to thecamera, the camera including the aperture, the mount adapter including adriver which drives the aperture; and a transmitter which sendsinformation of a minimum aperture value of the aperture to the camera.34. An exchangeable lens which can be directly or indirectly detachablyattached to a camera or an accessory through the camera, the lenscomprising: an optical system including an aperture; and a driver whichdrives the aperture so that an aperture value of the aperture fordetecting a focal position of the optical system becomes in a range of asecond aperture value or more and the first aperture value or less whenthe aperture value for capturing an image is larger than the firstaperture value, the second aperture value being larger than a minimumaperture value and smaller than the first aperture value.
 35. Theexchangeable lens as set forth in claim 34, wherein the driver drivesthe aperture so that the aperture value for detecting the focal positionof the optical system becomes the first aperture value when the aperturevalue for capturing the image is larger than the first aperture value.36. The exchangeable lens as set forth in claim 34, wherein the driverdrives the aperture so that the aperture value for detecting the focalposition of the optical system becomes in a range of the second aperturevalue or more and the first value or less when the aperture value forcapturing the image is in the range of the second aperture value or moreand the first value or less.
 37. The exchangeable lens as set forth inclaim 34, wherein the driver drives the aperture so that the aperturevalue for detecting the focal position of the optical system becomes athird aperture value when the aperture value for capturing the image isthe third aperture value, and the third aperture value is smaller thanor equal to the first aperture value and is larger than or equal to thesecond aperture value.
 38. The exchangeable lens as set forth in claim34, wherein the driver drives the aperture so that the aperture valuefor detecting the focal position of the optical system is less than thesecond aperture value when the aperture value for capturing the image issmaller than the second aperture value.
 39. The exchangeable lens as setforth in claim 34, wherein the driver drives the aperture so that theaperture value for detecting the focal position of the optical systembecomes a third aperture value when the aperture value for capturing theimage is the third aperture value which is smaller than the secondaperture value.
 40. A camera comprising: an imaging sensor whichcaptures an image by an optical system which includes an aperture andoutputs a signal; a detector which detects a focused position where animage by the optical system is focused in the imaging sensor based onthe signal; and a controller which sets an aperture value of theaperture for detecting the focal position by the detector in a range ofa second aperture value or more and the first aperture value or lesswhen the aperture value for capturing an image by the imaging sensor islarger than the first aperture value, the second aperture value beinglarger than a minimum aperture value and smaller than the first aperturevalue.
 41. The camera as set forth in claim 40, wherein the controllersets the aperture value for detecting the focal position by the detectorto the first aperture value when the aperture value for capturing animage by the imaging sensor is larger than the first aperture value. 42.The camera as set forth in claim 40, wherein the controller sets theaperture value for detecting the focal position by the detector in arange of the second aperture value or more and the first value or lesswhen the aperture value for capturing the image by the imaging sensor isin the range of the second aperture value or more and the first value orless.
 43. The camera as set forth in claim 40, wherein the controllersets the aperture value for detecting the focal position by the detectorto a third aperture value when the aperture value for capturing theimage by the imaging sensor is the third aperture value, and the thirdaperture value is smaller than or equal to the first aperture value andis larger than or equal to the second aperture value.
 44. The camera asset forth in claim 40, wherein the controller sets the aperture valuefor detecting the focal position by the detector to a aperture valuesmaller than the second aperture value when the aperture value forcapturing the image by the imaging sensor is smaller than the secondaperture value.
 45. The camera as set forth in claim 40, wherein thecontroller sets the aperture value for detecting the focal position bythe detector to a third aperture value when the aperture value forcapturing the image by the imaging sensor is the third aperture valuewhich is smaller than the second aperture value.